What is Placenta and Placentation

Placenta:

The organ which is formed by the combination of foetal tissue and maternal tissue for the exchange of nutrients and gases are called as placenta.
    The foetal tissue is the part of foetus and maternal tissue is from uterine wall of mother.

Placentation:

The intimate relation between uterine wall of mother and foetal tissue which is  mainly from chorionic membrane of foetus for the exchange of nutrients, minerals, respiration and excretion is called Placentation.

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