C. It's necessary for the survival of the individual
Carpet, meta carpel and phalanges
the answer for your question is C
A signal cascade is a series of chemical reactions which are triggered by a stimulus acting on a receptor that is then transduced to the intracellular space through second messengers. Finally, effector molecules receive the signal causing a cellular reaction to the initial stimulus. A signal cascade is very useful because it facilitates and accelerates the communication between cells that could be in different parts of a living organism. This communication is vital for cell processes in complex multicellular organisms.