Answer: yolk sac
explanation:
the placenta does not develop for a long time so the alternate way of supplying the developing embryo is through the yolk sac which the embryo can receive nutrients and respiratory gas exchange through which the placenta will be formed later.
Can't help you with this answer
A star at the end of it's life cycle is called a white dwarf (answer D). The order of life in the answer choices given is giant, red dwarf, white dwarf and nova. The nova, while the final stage is actually the explosive death of a star. The white dwarf state is a small, hot star that is that is dense in composition and composed of mostly carbon and oxygen.
Homeostasis is fulfilling equilibrium so having every function completely balanced