This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General physiology, Subject name: Physiology
Within the endocrine system, specificity of communication is determined by 
Select and explain. 
A. The chemical nature of the hormone, B. The distance between the endocrine cell and its target cell(s), C. The presence of specific receptors on target cells, D. Anatomical connections between the endocrine and target cells
C: The presence of specific receptors on target cells
Answer: C: The presence of specific receptors on target cells 
Explanation: Hormones produce their effects on target cells by interacting with specific receptors. Hormone binding to its receptor generally initiates a cascade of events that lead to biological effects in the target cells.