Why are there often so many steps between the original signal event and the cell's response?
A. Long, highly specific pathways minimize the possibility that a relay molecule accidentally could activate a pathway leading to a secondary response.
B. The accumulation of genetic mutations over time has added redundant steps to the pathway.
C. Each transduction is a checkpoint.
D. Lengthy pathways provide the opportunity for the initial pathway molecules to recycle back to inactive forms should additional signaling molecules be present.
E. Each step in a cascade produces a large number of activated products, causing signal amplification as the cascade progresses.
Answer: E