Correct Answer: D. Phytoplankton, Paramecium, Waterflea, Prawn, Tilapia, Shark

Explanation

(a)(i) Independent Assortment of Genes; is the random selection of genes during meiosis to produce gametes, where the genes separate/segregate so that only one of a pair is found in any one gamete. In the dihybrid inheritance in heterozygote the pairs of alleles are found on different pairs of chromosome, Only four types of gametes are produced in approximately equal numbers.

(ii) Blood grouping in humans; Is determined by three alternative genes/alleles A, B and O. A person can only possess two alleles of the genes on a pair of homologous chromosomes. Gene O is recessive to both genes A and B which are dominant/co-dominant and possess antigen A and B in the red blood cells hence it is possible to have blood group A as AA (homozygous) or AO (heterozygous) and blood group B as BB or BO, Blood group O can only exist genotypically as OO and does not possess antigen A or B in the red blood cells or in the homozygous recessive state.

(b) Classes of Vertebrates in their Evolutionary Trend;

Explanation

(a) Variation:These are morphological; and physiological differences; which occur within a species which could be hereditary or acquired from the environment.

(b) Advantages of variation: -Appearance of new varieties - variation allows survival of the fittest - competition arises - nature selects the most adapted varieties - that are more resistant to diseases - and better adapted to changes in the environment.

(c) Differences between continuous and discontinuous variation

(d)(i) Sex-linked characters: These are characteristics associated with the sex of an individual; the gene for the expression of the character; is borne on one of the sex/the X chromosomes.

(ii) Co-dominance:This is a condition in a heterozygote; in which both alleles have equal dominance; and the phenotype is a mixture of the opposing characters.

(iii). Hybrid vigour:This is the production of new varieties within a species; which are healthier/have greater resistance to diseases/are better adapted to the environment; as a result of out breeding/crossing non related members of a species.

Correct Answer: C. cerebellum

Correct Answer: D. Gene dominance

Correct Answer: D) Cholera

Explanation

Some diseases are transmitted through vectors such as mosquitoes and flies. Controlling these vectors can help reduce the spread of the disease. However, not all diseases can be controlled by killing the vectors. The question is asking which of the diseases listed cannot be controlled by killing the vectors. Option A is River blindness, which is transmitted by the blackfly. Killing the blackfly can help control the spread of the disease. Option B is Malaria, which is transmitted by the female Anopheles mosquito. Killing the mosquito can help control the spread of the disease. Option C is Polio, which is not transmitted by a vector but rather through contaminated food and water or contact with an infected person. Controlling vectors would not have any effect on the spread of the disease. Option D is Cholera, which is also not transmitted by a vector but rather through contaminated food and water. Controlling vectors would not have any effect on the spread of the disease. Therefore, the correct answer is Option D. In summary, not all diseases can be controlled by killing the vectors. Diseases such as Polio and Cholera are not transmitted by vectors and therefore controlling vectors would not help control the spread of the disease.

Correct Answer: B. cover-cropping

Correct Answer: B. Hygrometer

Correct Answer: C. morphological variation

Correct Answer: D. stomach and gall bladder