Correct Answer: B. the horrors of nightfall

Correct Answer: B. implementation of organizational plans

Correct Answer: D. ring placement

Explanation

(b) Methods of mining gold in South Africa

i. Shaft/Underground method.

(1) Involves underground quarrying

(2) Vertical holes are dug from the gold seam. (3) Gold bearing rocks are broken with explosives.

(4) Gold bearing rocks are taken through conveyor belts.

(5) The rocks are crushed and treated with chemicals to obtain Gold.

(6) Sent to smelters for further refining.

ii. Planning method.

(1) Used to recover gold from river alluvium

(2) Can be an individual.

(3) The materials needed are calabashes and pans.

(4) Sand bearing gold is collected from

river bed along with some water.

(5) The container is turned round and round. (6) The gold sinks to the bottom of the container.

(7) The useless sand on top us to collect the gold.

iii. Open cast method:

(1) Used where seam is close to the surface.

(2) removal of overburden.

(3) Explosives used to break the gold bearing rocks.

(4) The rocks are loaded on trucks with shovels.

(5) The rocks are taken to the crushing mill for extraction/concentration.

(c) Importance of gold mining to South Africa.

(i) Revenue to the government. (ii) Provision of employment. (iii) Provision of social amenities.

(iv) Foreign exchange earnings. (v) Provision of gold for ornament. (vi) Provision of gold as bullions for international currencies.

(vii) Income to workers.

(viii) Skill acquisition.

(ix) Raw materials for ancillary industries. (x) production of geological maps.

(xi) Attraction to great international investments.

(xii) Development of infrastructure In the mining areas.

(xiii) Improved standard of living.

(xiv) Uranium, a bye-product of gold mining is obtained and power.

(xv) Provision of valuable goods, e.g. necklace, earrings, etc.

Explanation

(a) The advantages of complex structural organisation in higher animals are:

(i) There is cellular differentiation or group of similar cells differentiate to form tissues that carry out similar functions.

(ii) Differential leads to internal structural specialization or the group of similar cells or tissues becomes specialised to carry out one or more functions.

(iii) It increases adaptation to environment.

(v) It leads to mutual interdependence between component cells or division of labour by component cells which leads to efficiency and increase in size.

(b)(i) Differences between colonial organisms and filamentous organisms are:

(ii) Examples of a colonial organisms are:- Pandorina / Volvox while that of filamentous organism is Spirogyra / Zygnema / Oscillateria

Correct Answer: B. 45^o

Explanation

In In the diagram given, \(\alpha\) = 22^o (vertically opp. angles), \(\alpha\) = \(\beta\) (alternate angles)

< PSQ + 133^o + \(\beta\) = 180^o (sum of angles of a \(\Delta\))

< PSQ + 133^o + 22^o = 180^o

< PSQ = 180^o - (133 + 22)^o

45^o

Correct Answer: A. Unite and not be divided

Correct Answer: B. supply schedule

Correct Answer: B. 1953

Explanation

Protective adaptations used by animals against predation

(i) Mechanical protection like the hard outer covering/ shell; e.g. giant snail/tortoise/oysters/barnacles/battery of spines in porcupine/sea urchin

(ii) Chemical protection in the form of poisonous secretions of skin glands; e.g. toad

(iii) Concealing colouration/cryptic adaptation/a close matching in appearance of the animal to its background; e.g. chameleon/praying mantis/green mamba

(iv) Specialised toxic glands/hairs linked to toxic glands/hairs that penetrate skin of predators/toxin secreted to cause intense irritation; e.g. larvae of Lepidoptera

(v) Mimicry of objects such as leaves or twigs; e.g. Praying mantis/stick insect/ moths

(vi) Rolling the body into a ball; e.g. pangolin/millipede/porcupine

(vii) Fast movement to escape from enemies; e.g. antelopes/deers

(viii) Secretion of offensive smell; e.g. shrews/zonocerus

(ix) Stings/injection of painful chemicals; e.g. bees/wasps/scorpions/electric fish

(x) Offensive structures of horns/hooves; e.g. antelopes/gazel/buffalos

(xi) Movement in groups to frighten predators; e.g. monkeys/baboons/small angulates

(xii) Detachment/dropping of parts of the body to escape; e.g. lizards/wall geckos

(xiii) Secretion of ink/coloured substance to impair vision of predator/create a screen e.g. squid

(xiv) Inflation of the body to frighten predator; e.g. chameleon/octopus/cats

(xv) And any other correct adaptive features and correct examples

(b)(i) Pollution

(a) The introduction of materials/ energy into the environment by humans (directly or indirectly)

(b) at such levels/concentration that affect biotic communities adversely thereby causing harm

(ii)Activities of humans which cause pollution

(a) Dumping of domestic/ farm refuse

(b) Release of chemicals from mines

(c) Misapplication of agro chemicals/fertilizers

(d) Spraying of pesticides and herbicides

(e) Dumping of broken bottles/glasses/ enamel wares

(f) Dumping of plastics

(g) Dumping of scrap metals

(h) Spillage of crude oil from pipelines/tankers

(i) Dumping of untreated sewage

(j) Effluent from factories/breweries/laboratories (i) Any other correct human activity