Vein because they have valves to prevent back flow of blood.
The answer is D.
An endothermic reaction involves absorbing heat whereas an exothermic involves releasing heat.
Answer is somatic; autonomic
The peripheral nervous system is made up of two systems; the somatic nervous system and the autonomic nervous system.The somatic nervous system is under voluntary control and transmits signal from brain to muscles, whereas he autonomic nervous system controls involuntary actions to regulate physiological functions such as working of cardiac muscles, bladder.
