How do signal molecules work in a cancerous cell?
a. cancer cells make their own signal molecules, are insensitive to them, or simply grow without them.
b. cancer cells can never interpret signal molecules correctly.
c. cancer cells interpret them backwards such that growth signals stop growth and growth inhibitors cause growth.
d. cancer cells use signal molecules just the way normal cells do.
e. they don't usually work at all.

About which of these did darwin have a poor understanding? a) that much of the variation between individuals in a population is inherited b) the factors that cause individuals in populations to struggle for survival c) the sources of genetic variations among individuals d) that individuals in a population exhibit a good deal of variation e) how a beneficial trait becomes more common in a population over the course of generations