Suppose that substance X is secreted by one cell, travels via interstitial fluid to a neighboring cell, and produces an effect on that cell. All of the following terms could describe this substance except
A) paracrine signal.
B) neurotransmitter.
C) prostaglandin.
D) pheromone.
E) growth factor.
Answer: D
If the answers is incorrect or not given, you can answer the above question in the comment box. If the answers is incorrect or not given, you can answer the above question in the comment box.