Correct Answer: excretion

Solution : The correct option is - Excretion.

All embryos contain the allantois, which is also known as allantoic. A clear fluid is contained within the allantois, which resembles a hollow sac.  The allantois has two functions: collecting liquid waste from the embryo and exchanging gases that the embryo uses.  The chorionic membrane, amniotic membrane, and allantois all aid in the embryo's growth.