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.

tsd is temerature dependent sex determination.

tsd: it is a type of environmental sex determination in which the temperature experienced during embryonic/ larval development (ambient temperature for development) determine the sex of the offspring.

crocodile displays the tsd where the ambient temperature of the developing egg determines the individual's sex. for example in the american alligator's eggs, incubation at 33 ºc produces mostly males, while incubation at 30 ºc produces mostly females. so if the american alligator's egg will get the ambient temperature (33 degree celcius)during embryonic development from egg, the offspring will be male and same for the female sex determination.

that is true   : ) hope this you