Which statement regarding chemical signaling systems is false?
A) Autocrine signals have an effect on the cells that secrete them.
B) Paracrine signals have an effect on nearby cells.
C) Signals carried by the circulatory system come primarily from the environment outside the organism.
D) A cell must have a receptor for a signal in order to bind to the signal.
E) A cell without a receptor for a signal is not a target cell for that signal.

Question

Quizplus · Accepted Answer

Signals carried by the circulatory system typically come from within the organism, such as hormones and neurotransmitters. They are not primarily from the external environment.

Which Statement Regarding Chemical Signaling Systems Is False