Hormone injected by doctors to induce delivery is

Each seminiferous tubule is lined on its inside by two types of cells $A$ and $B$. Which of the following options is correct, w.r.t. the type of cell and its function?

Nervous system in vertebrates develops from

Survival time of sperms introduced into the vagina may be

In the development of the human body, the ectoderm is responsible for the formation of