A female that is planning to become pregnant is concerned about her exposure to environmental mutagens which may have caused DNA mutations. In order for these mutations to become heritable, they must affect the:
A. her somatic cells
B. her skin cells
C. all her cells
D. her egg cells

D. her egg cells

Explanation: Mutations can only be passed down if the mutation happens in reproductive cells. Egg cells are reproductive cells. (Along with sperm in males.)

amber has allowed scientists to study dna that has been preserved over millions of years.

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.