Which of the statements about variation is not true? select one:
a. variation is differences in the size, shape, or color etc. of a particular species.
b. variation in a particular species allows for natural selection process to take place.
c. the amount of variation of a particular trait does not affect how quickly a trait evolves.
d. variation is necessary for a trait to evolve over time.

c. The amount of variation of a particular trait does not affect how quickly a trait evolves.

Explanation:

Variation is the diversity observed within a species. In a species all the organisms are not identical. They can vary in different characteristics like shape, size or colour. Variation can lead to natural selection because a particular variant of a trait can be favoured over the other ones and eventually  it becomes dominant in the population.

Evolution of a trait is also effected by the amount of variation present in that trait. More the variation, more different will be its response to the changing environment and more time can be required to incorporate these changes within an organism.

hydroxyl -oh

alcohols, always polar, can form hydrogen bonds with h2o molecules

carboxyl -cooh  

cargoxylic acids, has acidic properties which is a source of hydrogen ions, found in cells in ionized for with a charge of oh-1

carbonyl > co

ketone if within skeleton, aldehyde if group is at the end of skeleton, k & a may be structural isomers, it determines 2 sugars (ketose & aldose)

amino -nh2

amines, acts as a base, it can pick up h+ ions from surrounding solution, ionized with charge of 1+

methyl ch2

addition to rna/dna affects and gene expression

phosphate -opo3 ²⁻

organic phosphates, contributes to negative charge to, molecule that it is a part of, and potential to react with h20

sulfhydryl -sh

thiols, cross-linking stabilize the protein, and it is structure

the answer to your question is:

c. complementary base-pairing