Question

Give reasons for the following: (i) Why can a woman generally not conceive a child after 50 years of age? (ii) Polar bodies are formed during oogenesis and not during spermatogenesis.

Explain the structure of a mature embryo sac of a typical flowering plant.

How is triple fusion achieved in these plants ?

Describe the changes in the ovary and the uterus as induced by the changes in the level of pituitary and ovarian hormones during menstrual cycle in a human female.