Correct Answer: B. a contract

Correct Answer: C. composite demand

Explanation

Composite demand is where goods have more than one use. An increase in the demand for one product leads to a fall in supply of the other. An example is milk which can be used for cheese, yoghurts, cream, butter and other products

Correct Answer: C. hepatic portal vein

Correct Answer: A. Silver and trioxonitrate (V)

Explanation

(a) Distinction between agricultural systems: (i) monoculture is the practice of cultivating one and the same crop on the same piece of land every cropping season. Whereas, Monocropping is a practice of cultivating a single crop species each growing season and harvesting it before another crop is planted.

(ii) shifting cultivation is a farming system whereby a piece of land is cultivated continuously for some years and then abandoned as a result of the decline in soil fertility, build-up of pests and diseases, and the resultant reduction in crop yield. The farmer abandons not only the exhausted farmland but also his settlement for a new farm and a new settlement with no hope of coming back. Whereas Land rotation involves growing crops on a piece of land until it is exhausted and the land is left to fallow for some years before it is used again. The farmer clears other areas in succession to make new farms while remaining in his farmstead.

( b) Problems of commercial agriculture in West Africa.

-Inadequate supply of improved varieties of crops and livestock

-Unfavourable land tenure system/land fragmentation does not allow commercial agriculture to be practised

-High capital investment on machinery and other inputs/expensive machinery and other inputs

-Inadequate marketing channels Inadequate technical know-how on the operation and ,maintenance of farm machinery

-High Cost of spare parts

-Inadequate processing facilities

-In adequate skilled manpower

-Inaadequate credit facilities / subsidies

- Inadequate storage and processing facilities

-Inputs such as fertilizers, herbicides and pesticides used for commercial farming could pose health hazards to man and the environment if not properly applied

- It leads to the displacement of small scale farmers from their lands

- Unfavourable government policies

- It can lead to soil erosion.

(c) Uses of the farm tractor:

-Transportation of farm inputs, materials and farm produce / haulage with trailer attached.

- It operates water pumps for irrigation or other farm purposes

- Lifting of coupled implements through the hydraulic system

- Pulling of farm implements like ploughs, etc

- Titling the soil with appropriate implement attached

- Planting seeds when coupled with planters

- Spraying seedlings when coupled with sprayers

-Harvesting crops when coupled together with appropriate machines

-It can be a stationary power source for equipment like shellers, grinders, etc.

- Provision of electric power

- Can be used to operate milking machines

- Can be used for mowing lawn with mowers.

(d) Indigenous methods of sand preparation:

- Slashing / cutting

- Hoeing

- Felling

- Stumping

- Burning

- Mounding

-Ridging

Correct Answer: B. still determined and hopeful

Correct Answer: D. 135.5\(^o\) , 224.5\(^o\)

Explanation

cos x = -0.7133

x = cos \(^{-1}\)(0.7133)

= 44.496\(^o\)

x = 180 - 44.495\(^o\)

x = 135.5\(^o\)

and x = 180\(^o\) + 44.495\(^o\)

= 224.5\(^o\)

Correct Answer: B. life

Correct Answer: C. 3< m< 4

Correct Answer: D. Communities were interdependent