Explanation:



(a) Structure of the cell relating to its function
(i) Sperm cell

Has a long/whip-like tail/flagellum, with which it swims to reach the egg/ovum of the female organism.
Has a head with acrosome; for digesting/penetrating egg membrane
Has a nucleus in its head; which fuses with the nucleus of the ovum/egg cell during fertilisation to form zygote
Its middle piece contains mitochondria; for supply of energy/ATP.

(ii) Palisade cell

Has thin wall; for easy penetration of light
Has numerous chlorosplasts in peripheral cytoplasm for maximum absorption of sunlight
Has large vacuole containing cell sap; for temporary stor-age of products of photosynthesis.

(b) Diagram of the front view of the female reproductive system

Differences between reproduction in Mammals and Amphibians

Mammals	Amphibians
fertilisation is internal	fertilisation is external
Development of offspring is internal / viparous born young ones alive	development of offspring is external / oviparous/ lay eggs
placenta is present	placenta is absent
shows parental care	does not show parental care
produce fewer eggs / offspring	Produce numerous eggs/offspring

(d) Methods of birth control in humans

Abstinence
Use of contraceptive pills/injection of hormonal drugs
Coitus interruptus/withdrawal method
Safe period/rhythm method
Sterilization of men/vasectomy
Sterilisation of women/tubal ligation
Use of condoms/female condom/male condom
Use of spermicide/foam
Use of implant/Norplant
Use of IUD/intra-uterine devices
Use of diaphragm.