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