(a). Explain briefly the following terms: (i) Renewable natural resources (ii) Non -renewable natural resources; (b) Give two examples each of: (i) Renewabl...

(a) Explanation of terms

(i) Renewable natural resources: natural resources that can be replaced by natural processes or re-grown after use, so they are not permanently exhausted, for example forests, fish and water.

(ii) Non-renewable natural resources: natural resources that are present in fixed amounts and cannot be replaced within a human lifetime once used up, for example crude oil, coal and mineral ores.

(b) Two examples each

• (i) Renewable: forests (timber) and fish (wildlife). Water and solar energy are also acceptable.
• (ii) Non-renewable: crude oil (petroleum) and coal. Natural gas and metallic ores are also acceptable.

(c) Five ways of conserving forests

1. Afforestation and reafforestation (planting new trees to replace those felled).
2. Selective felling of only mature trees instead of clear felling.
3. Preventing and controlling bush burning.
4. Establishing and protecting forest reserves.
5. Enacting and enforcing laws against indiscriminate cutting of trees.

(d) Four effects of adding animal manure to garden soil

1. It adds humus and improves the fertility of the soil.
2. It improves the soil structure and aeration.
3. It increases the water-holding (moisture-retaining) capacity of the soil.
4. It increases the population of useful soil micro-organisms and releases nutrients as it decays.

(e) Possible genotypes in humans

Taking a single gene pair with a dominant allele and a recessive allele (for example alleles A and a), the three possible genotypes are:

• \(AA\) - homozygous dominant
• \(Aa\) - heterozygous
• \(aa\) - homozygous recessive