Highlight the differences and a similarity between the following population interactions:

competition, predation and commensalism.

Why are there regular reminders to reduce the use of CFCs in theproduction of industrial and household appliances? Explain.

Mention the relationships between pituitary and ovarian hormones during a menstrual cycle.

(a) Name the types of flowers produced by Viola (Pansy). How do theydiffer from each other?

(b) Describe the kind of pollination in one of the types of flowers that ensures seed-set production.

(c) Describe the process of pollination in Vallisneria.

OR

(a) Describe the technique that can help a healthy married woman who is unable to produce viable ova but wants to bear a child.

(b) Draw a labelled diagram of a human ovum.

(c) How is polyspermy prevented in humans?

Write the role of histone protein in packaging of DNA in eukaryotes.