What is a process by which organisms with characteristic suited to the environment will survive and reproduce

According to Charles Darwin's theory of Evolution by natural selection, organisms that possess heritable traits that enable them to better adapt to their environment compared with other members of their species will be more likely to survive, reproduce, and pass more of their genes on to the next generation.

(n.d.). Retrieved from http://www.nas.edu/evolution/Definitions.html

One word Adaptation:

the answer to your question is:

c. complementary base-pairing