Environmental variation a. tends to blur together the phenotypes associated with different genotypes. b. has no effect on phenotype. c. affects genotypic expression of characters. d. does not direct selection.

c. affects genotypic expression of characters.

Explanation:

Environmental variation like food, variation, humidity, oxygen, etc affects the expression of characters which is seen in the phenotype. For example, in crocodiles and some reptiles, the incubation temperature in which their eggs are present determines the sex of their offspring.

This shows that temperature affects their genotype and allow expression of some genes more which can be seen in their phenotype. Therefore environmental variation plays an important role in the expression of characters by affecting genotype.

a. the production of carbon dioxide through the process of photosynthesis