The stem cells which have the potency to give rise to all tissues and organs are formed from:

During embryonic development,after the third cleavage,the number of blastomeres formed will be . . . . . . .

The cavity formed during gastrulation is known as:

Foetal ejection reflex in human female is induced by

What is a twin?

In the simplest type of placenta,the foetal blood is separated from the maternal blood by six barriers. How many barriers are lost in the human placenta?