Answer:
A.
Explanation:
A parasite does not feed it's host; in fact, it takes food energy/ food from it's host.
It can't be released by photosynthesis
Because hormones secreted by endocrine glands regulate the activity of body cells ..the release of body hormones into the blood is controlled by a stimulus either causes an increase or a decrease in the amount of hormone secreted .
It is because of the different neurotransmitters and their receptors.
Sympathetic stimulation of arterioles in skeletal muscle is mediated by epinephrine acting on its β-adrenergic receptors.
Sympathetic stimulation of vasoconstriction occurs as a result of activation of α-1 adrenergic receptors by norepinephrine released by post-ganglionic sympathetic neurons.
