Which one of the following events immediately follows the entry of a spermatozoan into an oocyte
An increase in the permeability of the oocyte membrane
An increase in activity of proteolytic enzymes
A decrease in the metabolic rate of the oocyte
Thickening of the vitelline membrane
Vasa deferentia together with seminal vesicle forms
The placenta of human beings belong to the category of
Embryo at $16$ -celled stage is called
Menstrual cycles ceases : Menopase :: First menstruation begins :
In menstrual cycle other name of follicular phase is....