Bio-score Form 4 Chapter Answers sheet

Bio-Score Teocher's Edition 2008

E

9.1

HUMAN ACTIVITIES THAT ENDANGER AN ECOSYSTEM Learning outcomes:

o o o o o o o o o o o o o

b

Identiff human activities that threaten the ecosystem, Explain the impact of human activities on the ecosystem, Evaluate critically the effects of unplanned development and mismanagement of the ecosystem, Describe types of pollution and sources of pollution, Explain the effecL of pollution on living things and the environment, Compare and contrast pollutants ln the air from different environments, Sbate the sources of air pollution, Interpret data on the level of air pollution in sorne cities, Make an inference on the sources of air pollution in some cities, Interpret data on the level of water pollution in some rivers, Make an inference on the sources of water pollution in some rivers, Predict the level of air and water pollution in a particular location within the next ten years, Suggest strategies to solve problems related to air and water pollution in a particular location within the next ten years.

1

The impact of human activities on the ecosystem Many problems related to the environment are the result of human activities and human interference in the ways ecosvstems function. The examples of devastating human activities on the environment are deforestation, bad agricultural practices, active mining activities, industrial activities and also domestic activities.

At In

Deforestation

stl

Deforestation is the permanent removal of trees from the forests for infrastructural development, toqginq industries,

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urbanisation and plantation.

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the oldest ecosystem on the Earth and home to almost half of the world's flora and fauna

The imoacts on the environment.

contain many unique species which provide

. . . o

human

r

a.

Deforestation

foods, medicines and other resources for

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In<

ffi

lmportant roles of tropical rainforests;

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regulate the world climate act as a carbon sink of the Earth because they

soil erosjon

b

flash flood

landslides global warming

absorb vast amount of carbon dioxide during

a

severe climatic changes e.g. drought

photosynthesis and at the same time release oxygen into the atmosphere

a

the loss of biodive,rsitv

a

destruction of natural habitat that leads

?s water catchments areas where rain water is

to ex.tinction of many animal and

absorbed and released back as water vapour to

species

the atmosphere.

destruction of recreational sites

,

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Bad Agricultural practices Among the bad agricultural practices carrred out by some farmers are.

1.

The use of excessive inorganic fertilisers,

pesticides and herbieides ihat would pollute the water sources and affect the fresh water ecosystems.

2.

lntensive farming of crops and livestock which cause changes to the soil structure

. o

Continuous cultivation of the same plot of land.

l1

The plouqhinq of land down the slope instead of along the slope

.

contours.

Erosions of

Overqrazinq by livestock that does not permit the grass to grow back.

topsoil by flowing water

' "

when

The loss of topsoil nutrients. The

sihi{g

of the bottom of rivers and lakes with earth sediment

it

rains.

)

causinq flash floods

Active mining activities ln Malaysia, the high water pressure used in the open tin mining activities alters the land surface structure.

lndustrial activities lndustrialisation leads to:

a.

lncrease demand for energy and natural resources. Thus,

o

mining activities for fossil fuels and metal ores increase and the natural environment would be destroyed.

r b.

damS are built to generate hydroelectricity, resulting in the flooding of large areas of land.

Environmental pollution due to:

"

the burning of fqss!! fuels such as petroleurn and coals, resulting in the enrission of gases such as carbon dioxide, sulphur dioxide and nitrogen oxides that pollute the air and lead to acid rain etc.

.

the dumping of solid wastes in dumpsites, stinking the areas and also pollute the nearby water sources.

.

the discharge of effluent that dissolve and suspend in water to deteriorate the water quality. .\atr Bio-Kit

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Domestic activities

1. Rapid human population growth

causes the development of housing areas that may aiso

contribute to pollution. Cause

r-1

lncrease in domestic wastes through:

l. Dumpinq of solid wastes 2.Discharge of sewaqe and detergents

Lead to

1. Land pollution 2. Water pollution

The impact of human activities on the ecosystern The major problems on the ecosystems that are caused by human activities include polluticn. greenhouse effect and thinning of ozone layer.

Pollution

a.

Definition of pollution: Pollution can be defined as any undesirable changes in qhvsical, chemical and bioloqical characteristics of the natural environment, brought about when harmful st-tbstances or energy are released by human activities.

b.

Types, sources and effecG of pollution:

i.

Air pollution Definition: The condition when pollutants enter the air frorn various sources. Sources:

'

Faqlories that pump large amounts of carbon monoxide, carbon dioxide. oxides of nitroqen and sulphur dioxide into the atrnosphere.

'

Exhaust fumes from motor vehicles contains soot, lead, carbon monoxide anci oxides of nitrogen.

'

Open burnings and forest fire that release excessive smokes with suspended solidp and pollutant gases such as carbon dioxide and carbon monoxide.

'

Coal-fired power stations that release large amounts of carbon dioxide into the atmosphere.

'

Quarries, cement factories and sawmills which emit dusts into the air.

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**"tion of haze and excessive smokes in air that: - decrease liqht penetration and cause the deposition of dust and carbon particles on the stornata of leaves. Photosynthesis would be affected and crop production is reduced.

-

reduce visibilifu and may lead to the closure of airports.

-

coat the buildings and structures with layers of carbon and dirt thus increase the maintenance costs.

cause health problems such as bronchitis, rhinitis, eye lrritation and conjunctivitis.

Acid rain Gases such as nitroqen oxides and sulphur dioxide combine with water vapour in the atmosphere, forming nitric acid and sulphuric acid vrhich then fall as acid rain. The adverse effects of acid rains are: - soil becomes more acidic and less suitable for planting of crops.

-

salts

in the soil would be dissolved and

carried into rivers and lakes. High level of certain salts such as aluminium salts may be poisonous to aquatic organisms.

-

erosion of iron bridges, metal railings and also the limestone or marbie structures.

-

afiecied plants growth when chtcrophvlls and photosynthetic tissues are destroyed.

Greenhouse effect and the thinning of ozone layer ("would be discussed under the next sub-topic)

I

l.

Water Pollution Definition: The concition when pcllutants enter the water sources such as lake. rivers and sea from various activities.

d

Sources:

" r€

Domesiic activiiies

-

the dispesaj oi solici wasies (e.g. rirbbish), deiergents and sewaq€ froil1 housing areas.

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lndustrial activities

-

untreated waste toxic chemicals (such as mercury, lead, zinc etc.) radioactive waste substances

Agricultural practices

'

the run-off from excessive use of fertilisers, pesticides and herbicides

shipping activities

-

crude oil spills from tanker ships

Effects:

.

Eutrophication

such as chernical fertiliqers

(phosphates and niirates) enter the rivers or lakes would enrich the water with nutrients. Photosynthesizi ng organisms

particularly algae that grow rapidly result in population explosion known as algal bloom.

High diversity of algae reduces water light intensitv hence lead to the death of other photosvnthetic organisms in the water. The decomposition of these dead organisms by bacteria cause severe deoletlon of water dissolved oxygen, causing the death of other aerobic organisms such as submerqed aquatic plants, fish etc. High BOD and the spread of water bome diseases.

rnicro-qrqanisms such as algae, bacteria and prQ(ozoa. These lead to the increase of BOD {BiologicallBiochemlcal OxyQen Demand). When

dissolved oxygen in water is reduced, the life of the living aquatic organisms would be affected. Thus, the high BOD value indicates that the level of water pol!*tlon is high. .(Biochemical/Biological Oxygen ciemand is the amount of oxygen utilised b,v

aerobic microorganisms to decompose organic rnatter in a particular

sample of water) lrefeetio{s- diseases such as chciera, tyrphcid, dysentery and hepaiitis A.

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Accumulation of ioxic materials. industries are the main sources of toxic pollution in water resources. organic chemicals toxins such as DDT, benzene etc in water woutd accumulate in the benthic organisms and the producers, which woutd be passed up to the higher rever of organisms via food chains. Bioaccumulation of these metal ions and toxic chemicals would cause devastating effects in humans such as the damage of body organs and gene mutation that wourd read to cancer and reukaemia. Environment disaster Spillage of crude oil from oiltankers into the sea can cause major environment disaster. The layer of oil on the surface of sea would:

photosvnthetic activities of aquatic plants are disturbed. affect the organisms living in the water.

poison certain animais when they come in contact with this oil. damaged animals fur and birds feathers when coated with oil, thus they could neither fly nor escape themselves from predators. They could not aiso keep their bodies warrn but will die by freezinq to death. In-

Thermal Pollution

Definition: The condition where the temperature of the

lncreases

when excess heat is released into ihe environment. Sources:

" '

Reflection of heai from glass buildings that increases the temperature of surrounding air.

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Factories that use water to cool down machinerieq release warm water into the rivers, lakes or seas. Nuclear reactors release hct water into the rivers, lakes or seas. I

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Eifects:

"

Many aquatic crganlsr:rs wculd die as they cannot toleiate the rise in tne su;-iounding water temperature. The increase in water ter,nperq-turs

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much as S'C above the normal water temperature would be fatal to aquatic organisms that only survive within a cet'rain range of temperature.

lncrease

in BOD value when the metabolic rate of aquatic organisms

increases.

Warm water contains less dissotved oxygen for the respiration of aquatic organisms such as the planKons, thus the food webs are disturbed when planktons die.

.

Miqrations of organisms occur when the food chains are affected and the ecosystem balance is disturbed.

iv.

Noise Pollution

Def,nitiol: The condiiion where the unwanted human-created sound disrupts the environment or becomes harmfulto human health and welfare. Sources:

F -t*

. trains . aeroplanes

:m"il:';;"" '

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drilling machines and piling in construction sites

Effects:

.

Decrease in hearing sensitiviiy when someone is continuously exposed to the noise level at about 80 decibels (dB) and above, which wifl finalty lead to

deafness {since the safe noise level is < 55 dB according to WHO and the noise at 140 dB damages the auditory organs).

'

Development

of health problems such as indigestion, ulcers, high blood

pressure, coronary disease, depresgion and headachesFacts to share: Noise levelidB) 40-60 80-1 00

Effects

Noise types

Nonnal conversation Food blender, lawn mower, heavy traffics, tractors

) 100

Piling, drilling, rcck concert

) 125

Jet enqine, shctgun

Safe for the ear.

Annoying and continuous exposure Ieads temporary hearing damage. lf not treated can cause permanent damaqe. Unprotected regular exposure cause cermaneni hearino loss. Hirth poteniialfor hearinq loss.

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9.2

2OOB

THE GREENHOUSE EFFECT AND THE THINNING OF THE OZONE LAYER. Learning outcornes:

o c c o

Erylain what greenhouse e{fect is. Correlate the concentration of carbon dioxide in the abnosphere with gtobalwarming. Explain the thinning of the ozone layer. Explain the impact of thinning of the ozone layer and global warming on the ecosystem.

The Greenhouse Effect

1. When sunlight reaches the Earth, the

Earth,s

surface absorbs the energy and reflects it back into the atmosphere in the form of infrared radiation (lR).

Some of this infrared radiation goes back to the space but some is absorbed by the pollutant gases (greenhouse gases)

in the

atmosphere (such as methane, water vapour, carbon monoxide and particularly carbon dioxide) that re-emit the energy back to the Eaiih's surface as heat, causing the Earth to heat up. This phenomenon is known as qreenhouse effect. 2.

The greenhouse effect is actually responsib{e for keeping the Earth warm and suitable for life but nowadays as the greenhouse gases increase, more heat energy is trapped in the atmosphere and the Earih ternperature is continuously rising. This excessive

heaiing of the Earth surface is known as globa! warrning The world greenhouse gases rise due to:

a. motor vehicles b, coal-fired power stations c. industrialisation d. forest fire e. open burning of rubbish f- deforgstation {cause the increase !n carbon dioxide concentration due to the decrease in photosynihesis activity) The effects of global warming include:

a.

The meltinq of ice and icebergs in the pElar region that raises the sea levej and subii-:ei"ges ihe c_qastai r=sidenilal ai-eas anc aciic:iiure lands.

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The change of the world climate

i"

High rate of evaporation causes the drying up of lakes and rivers, causes

ii.

droucht and expand deserts. Changes in wind directions and sea current cause natural disaster such

as

hearry rains, flash floods, strong winds, typhoons, hunicanes etc, C.

Deterioration of health

i. ii.

High temperature lead to heat stroke

The widespread of epidemic diseases after flood

iii. Lack of food and malnutrition caused by

low productivity

of crops and

livestock due to drought and flood.

The Thinning of Ozone Layer 1. The ozone layer is a region

in the stratosphere between 17 and 25 kilometres above the Earth surface"

2.

The function is to shield the Earth from receiving too much of ultra violet (U$.

t{igh intensirl* of 1 ultravrotet ral's t

The thinninq of ozone layer has been recorded since the 1970s. The area with

very low ozone concentration ends up with the formation of ozone hole. 4.

Since 1980's, a huge hole in the ozone layer has been found opening up over Antarctica and similar thinning occurs over the Artic region. The ozone hole increases the intensity of ultraviolet radiation [n the earth atmosphere.

5.

The destruction of ozone layer is due to the increasing levels of chlorofluorocarbons (CFCs) in the atmosphere.

6.

€one

CFCs are a group of chemical compounds that

K=F:s --

contain chlorine, fluorine and carbon.

7.

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CFCs are widely used as coolants in air

conditioners and refrigerators, as plopel.lqxls in aerosol cans and as foarning agents in the making

of polystyrene packaging, pillow, cushions etc-

B.

The chemical processes that destroy the ozone layer are as follow:

i.

The CFCs in the atnrosphere are struck by UV iight fornring chlorine atoms.

CFC13 w,

Cl +

{Trichlorofluorocarbcn) (Chlorine}

CFC}2 {Dichiorofluorccarbon)

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ii.

Chiorine atom then breaks the ozone molecule into chlorine monoxide and oxYgen gas.

C1 +O3ClO+02

(Chlortre) (Ozone)

iii.

(Chlorine

rnonoxide)

(gnrygen molecule)

Ghlorine monoxide then reacts wiih the free oxygen atom in the atmosohere to form chlorine atom and oxygen mofecule.

ClO+O-)C1

(Chlorine

iv.

9.

2OOB

monoxide)

(Oxygen

atom)

*Oz

(Chlorine

atom)

(Oxygen molecule)

The chlorine atoms repeat the bre+kinq of the ozone molecules causing the depletion of the ozone layer continuously.

The impacts of ozone depletion on humans and the ecosystems:

i.

Increase greenhouse effect.

o ii.

Skin Cancer

o iii.

Earth temperature increases when more UV (ultra violet) radiation reaches the Earth surface and more IR (infrared) radiation is reflected into the atmosphere. Long exposure to sunlight may cause skin cancer, especially to those with falr skin (less melanin to protect oneself from UV tight).

Cataract

o

Eye lens become opaque leading to blurred vision which can eventually end with blindnes-s.

iv. Damaging the photosynihetic mesophyll layers of plants. o Reduce crops productions and destrr-lction of forests. v. Reduced human immune system. o Human beings are exposed to various diseases vi. Disturb the ecoiogical ba{ance by

destroying aquatic organisms especially

phytoplanKons.

10- Ways to overcome the problems of the thinning of ozone layer: i. Reduce or stop the use of CFC

tt- Substitute CFC wiih HCFC {hydrochlorofluorocarbon) that has less potential

to

destroy the czcne layer^

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9.3

THE IMPORTANCE OF PROPER MANAGEilIENT OF DEVELOPT$ENT ACTIVITIES AND THE EGOSYSTEM. Learning outcomesr o justify the need of develoPment o explain the effect of increase in population on the ecosystem o explain measure taken in the management of development adivitis and ecosystem to ensure a balance of nature is maintained o care for the ecosYstem o participate in activities related to the managernent of the ecosystem

The needs for development

1.

Development has to go on to provide the basic necessities and to improve the qualfu of life L{

of the increasing population.

2.

is

More lands must be cleared for:

a.

Agriculture

c.

Building infrastructures such as roads, houses, schools, hospitals, power stations etc.

- to increaseloog production b. lndustries - to prepare job opportunities

3.

Therefore, development activities shoutd be carried out without destrovinq the natural resources and by taking into consideration the environrnental impacts.

Environment as resources for life

1"

Source of toods, drinks, medicines etc.

Examples: Fresh water for drinking, fish for proteins, honey for food, herbs for medicine etc.

2. Place to live 3. Sources of enerEv Examples: Renewable sources. Solar, wind, wave, fossilfuel. Non-renewable sour€s: Petroleum, coal, natural gas.

4- All these

sources must be managed properly to ensure continuous utilisation by hurnan

beings. The effect of irnpropei'rfianagernent of developrnent

Many developmental projects implernenied would upset the balance of ecosvslgrn. These include:

1. The destruction of habitats and eNtrnc'tlon of animal and plant species when

}ands are

developed for agriculll,$ai activities, hgusinq projects etc.

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Poisoning of lands when pesticides, insecticides and chemicalfertilisers are widely used. J, The pollution of the environment caused by the emission of toxic substances into the water, 2.

air and land. 4.

Lost of soil fertilitv due to soil erosion, leaching, drought etc. Upset food chains

-

when mono-cultural farming

{planting only one type of plant in a big way) is practiced. o.

lmbalance of ecosystem caused by destruction of natural cycles carbon cycle, nitrogen cycle,

water cycle etc. Itdeasures taken in management of development activities to ensure a batancect nature is maintained 1- Sustainable development is the continuous development activities with minimum

irnpacts on the environment.

2-

Our demands for resources have to be balanced with the needs in order to sustain the resources.

3.

Measures taken to maintain the balance of nature are:

a- By the implementation

and enforcement of environmental laws:

Examples.

i. ii-

Environmental Qualitv Act 1g74, {Revised 1985 and Amendment 1g96) Cornposed of 6 regulations retated to air, vehicles srnokes and gases, clean air, rubber, oll palm, sewage and industrial effluqtts. National ForestryAcL 1g84

Forestry and Wld Life Departments are appointed to protect our national forest and the wild animats. iii.

Pesticides and Herbicides Act. 1974.

iv.

Factories and Heaw Machines Act 1g67. 1983.

Environmental Qualitv {sewaqe and lndustrial Effluents) 1grg.

vi. L.

U.

By making use of technology. Exampies:

i- Use catalytic converters

in cars io clean exhaust emission and special fihers on industry chimnbys tc filter- the release of scct, teed parlicles and toxic gases inio ihe airnosphere.

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ii. Treat the heavy metals and toxic components in liquid factory effluentiii. Use non*!ea1!gg[ petrol. iv. Recvcle the waste products.

v.

lncinerate the qarbage.

vi. Use micro-organisms in cleaning up the environment. vii. lntroduction of solar powered or electric powered cars.

c.

By educating the citizens on the managernent of resources:

i.

lntegrating the formal environmental education into the formal education systern in

the efrort of producing generations who are conscious enough on the problems related to the environment and skilfulin solvinq the related problems. Exainples:

.

lntroducing the study of environr4ent at school level as early as possible.

.

Establishment of Environmental Faculty in the local universities such as in UPM etc.

ii. Giving informal education to the pubiic in the effort: . to raise their awareness and responsibilities towards the environment. . to increase their responsibilities not to pollute the ecosystems but create

a

cleaner and healthier living environment. Examples.

TV, newspapers, magazines, pamphlets and pcsters"

environment by govemmental agencies and also the non{ovemmental agencies such as SAM (Sahabat Alam Malaysia), \At1l/F (World Wildlife Fund) etc.

d- By preserving

i. ii. iii. iv.

and conserving the natural resources.

Restoring used mining lands for agniculture,

Replanting forest trees that have been cut down to rnaintain the supply of wood for the future and to prevent erosions. Restore polluted rivers tc ensure surfficient supply of water for the future.

Conserving mangrove swamps as they are important ecosystems for the breeding of many ani;'nals.

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By practicing biological control. Biologicat control is the method of controlling the population of animal pests using animal predators. This method is more suitable since using pesticides would affect the food chains. Fxamples of biological controls are:

i. The breeding of owls to control the rat population in oil patm estate. ii. The use of guppy fish to eliminate mosquito larvae. iii. The use of female insects lchneumon that produce larvae which feed the caterpillars that bore into the paddy stems.

f.

By making use of renewable energy resources. Examples:

i. ii. iii.

g.

The use of solar energv.

The use of bio-fuels such as blodiese! {from palm oil) in replacing non-renewable fossilfuels The use of bio-sas (e.g. catfle dung to produce methane gas)

By efficient use of enepgy.

i-

Efficient use of non-renewable energy resources like fossil fuels and nuclear fuels must be planned and manaqed carefully.

ii-

We have to develop uses of altemative energy resources especially renewable energy resour€s like solar, wind, water and biomass energy. These energy resources

€n be used more efficiently without much

damage

to

our

environments.

iii.

Some of the ways that we can use energy efficienfly include:

. . .

Using energy-saving electrical appliances. Using fluorescent lamps which are more energy efficient.

Using pressure cooker and cooking utensils made of good conductors of heat to reduce cooking time and energy used.

"

Use public transports such as buses and LRT instead of own car. Car pooling will also help to reduce the use of energy.

.

New buildinss should be designed to be more energy efficient. The buildings shouid be well-ventilated, making use of solar energy and making maximum use of natural light.

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EXERGISE:

Part

I

Structured questions

1. Diagram

1 shows

the effect of human activities on the ecosystems.

'€i4

a"

Diagram

1

Name the activity canied out in Diagram 1.

Deforestation

(1 mark)

b- Give two purposes of carrying this activity. *Any

two of fhese (Housing development, road cnnstruction, agriculture, mining, (2 marks) industialdevelopment, urbanisation etc-)

c.

Give three functions of tropical rain forests. *Any three of fhese: . home fo almosf half of the worldb flora and fauna

.

contain many unique species which provide foods, rnedrbtnes and ather resources for human

. e

reguiate the woid climate &ct as a

cadon srnk of fhe Eafth because ff:ey absorb vasf amount of catbon dioxide

during photosyntliesrs and at fhe same fime release axygen into the atmosphere

.

d.

as water catchmenfs

areas

{3 marks)

Exptain the effect of the activity to biodiversity.

Effect: Explanation:

Decrease in biodiversify

o o o

Losi of habitats and foods The number of plants and aninals decreases Sorne planf and animalspecrbs become exfincf

(4 marks)

e.

Name two geochernical cycles that may change due to the activity Any two of fhese (" water cycle, carbon cycle, nifrogen cycle) (2 marla)

..i?. )

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Diagram 2 shows a factory discharging effluent into a lake that lead io pollution.

Diagram 2

What is the lype of poilution occurred? Water tr U

pollution

(1 mark)

If the facory is a textile faciory that discharge dyes into the lake, narne two heavy metal ions that couid be found in the lake water: *Any two of metalrbns fe-g iran, mercury, capper, zinc, atuminium

c.

etc)

(2 marks)

what would happen to the heavy metal ions in the lake water? undergo bioaccumulation in fhe fr'ssues of the lake aquatic organr.sms (1 ma*)

d.

\tYhat is the biologicalterm used when the level of metal ions in the tissues

keep on increasing?

Biomagnification ;

It.

mark)

would happen to the fisherman Yl"t fish caught

and his family if they continuously feed on the from the lake? Give reasons to support your answer in e(i). I.

ii.

They willhrie senbus illnesses srrch as cancer, [eukaemia, paralysrb efc. Reasons.' - Metalrbns are non-biodegradable but remains (bioaccumutate) in the human body fibsses.

'

f.

ft

Long term feeding of frsh from the /ake causes biomagnificatjon of these meta! ions in the human bady fi'ssues High level metal ions in the bady fi.ssues coutd inhibit certain enzymatic reactions in the body orcauses gene mutation that jead var[ous #Inesses. (4 narks)

Suggest three actions to be taken in order to avoid the fisherman and his family from hiring the diseases related to the effects of heavy metal ions.

i.

Bv the ima{ementation and enforcenent of environmentat laws-

Govemment through legis{atian, rnust take acion

ii.

ai tne companytfactory

management to protecf fhe desfruction of the natura[ resources. SJ makinq use af tech The factory musf freaf the heavy rnefals and toxic components eff]uent befare drbcira4ring it inia the ltrafer sosrces.

in the liquid of factory

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Diagram 3 shows various human activities that involved the buminE of fossil fuels, + w_i..+rl ----,1>-^'"i

(

a.

{

Diagram 3 Name the gases emitted from the buming of fossil fuels.

* Any three of fhese gases ( cafian

drbxrde ,carban manoxide, sulphur dioxide, diaxide) f3 marks)

nitric oxides/oxides of nrfrogen (nitrogen manoxide, nitragen

b. i. What would happen ii.

when the gases dissolve in atmospheric water vapour?

Explain the effects on aquatic ecosystems?

i. ii.

Acid nin will beformedThe ecolagical balance af aquatic ecosysfern wi{l be disfurbed because many types phytoplanfton, zooplankfon, fsh and other aquatic species witl be desfroyed.

of

{3 marksJ

Smoke, dust and soot can combine with cloud particles to form haze that darken the air and reduce visibility.

i.

What is the effect on the productivity of agriculture? Explain your answer in c(ii

i ii.

The agiculture productivity will be reduced Explanation: o Haze prevents sunlight fram reaching the earth and /owers the eaftlt temperature.

o lhe nte of photosynfhesrs of fhe pianls decreases grovtth and crop productian, d. Suggest three ways to reduce the problenrs caused *

that atrect ptants {3 marks}

by excessive smoke and haze.

Any of these answers.'

i. ii.

Use catalytic converfe,'s rn cars fo clean exhausf eml'ssion

Fx speck/ filters on industry chimneys to filter fhe release cf soof, lead parlicles and toxlc gases info the atmosphere.

iii. lncinerate the garbage. iv. Avoid open buming v. Contro! forest fire vi. Use fueis whtch rslease less s,':roke

i3 mar,ks;

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EKSPERIMENT An experiment was carried out to investigate the level of water pollution in three different sources of water : well \+ater, pond water and river water, The following steps were carried out. Step 100 ml of each water sample was placed in a reagent bottles. : 1 ml of 0.1olo methylene blue solution was added to the base of Step each of water sample by using a syringe. Step All the reagent bottles were closed and placed inside a cupboard and the time taken for the methylene blue solution to decolourise was recorded.

1 2 3

Diagram

:

:

4 shows the apparatus

set-up used in this experiment.

_ 250 m} reagent bottle EE+ water sample

syilnge 0-1% of methyiene blue solution stopper

water sample + 0.1% of methylene blue solution Diagram 4

(a) In Table 1, list all the materials

and apparatus labeled in Diagram 1.

Material (M)

1. vr4