Draw a neat labelled diagram of a transverse section of human ovary.

a) Write four characteristics that have developed during human evolution.

(b) What are stem cells? Write two applications of stem cell in medical treatment.

(c) Mention three basic ways to conserve plant resources.

Explain natural selection on the basis of sickle-cell anaemia.

(a) Define:

(i) Vestigeal organs

(ii) Sympatric speciation

(iii) Mutagens

(iv) Biogeography

(b) Archaeopteryx is considered a connecting link between reptiles and birds. Justify the statement by giving two characteristics of each group.

(c) Give two differences between natural selection and artificial selection.

(a) Explain four measures to control population explosion.

(b) Write the causative agent and main symptoms of the following diseases
(i) Tuberculosis (ii) Tetanus
(iii) Hepatitis (iv) Malaria

(c) Write two differences between benign tumour and malignant tumour.