How does Embryo get nourishment inside the mother's body?

Where is urea formed inside the body?

How plants get nutrients ?

Does cooking affect the nutrients in the body?

Mention the form in which inactive protein toxin is produced by Bacillus thuringiensis. How does it get activated in the pest body to kill it?

The blood of mother never mixes with that of foetus yet it nourishes the foetus, how?