The excretory system allows animals to remove metabolic waste their bodies. Many of these substances are potentially toxic. in Mammals nitrogenous toxins like urea are expelled through liquid urine while in reptiles and birds the nitrogenous compounds are expelled as a solid. This allows birds and reptiles to use less water in the processes of metabolism.
It form the contraction and relaxation of muscle
Answer:
A, C, D are responsible. B is irresponsible
Explanation:
the answer is the facial nerve
