In human females, an event that indicates the onset of reproductive phase is :

Which among the following are not the functions of testes at puberty?

(i) formation of germ cells

(ii) secretion of testosterone

(iii) development of placenta

(iv) secretion of estrogen

During adolescence, several changes occur in the human body. Mark one change from the following associate with sexual maturation in boys:

The off springs formed as a result of sexual reproduction exhibit more variations because :

One of the following occurs in the reproductive system of flowering plants as well as that of humans. This is :