Which of the following is true?

a. adaptation to the environment does not require heritable traits
b. adaptations can either increase or decrease fitness in a given environment
c. individuals with adaptations have higher fitness than those without the adaptation
d. a trait can be an adaptation regardless of its effect on fitness

The correct answer is option c. "Individuals with adaptations have higher fitness than those without the adaptation".

Explanation:

In evolutionary theory, adaptations are defined as the development or modification of biological mechanisms that helps an organism to adjust to a new environment. A modification in an organism must be beneficial in order to be considered an adaptation. Therefore, individuals with adaptations have higher fitness than those without the adaptation, and a better chance to survive to new environments.

b. read the phase at the intersection of any given temperature and pressure.