A radioactive material has a half-life of 30 days. You begin with 4 grams of radioactive material. a. How much of the original is left unchanged after 90 days? b. After 120 days?

potentially fatal issues such as heart attacks and strokes

explanation:

the right option is; decreased genetic variation  

decreased genetic variation describes the effect of this environmental change.

genetic variation is the naturally occurring genetic diversities or differences between organisms of the same species in a population. genetic variation allows the survival and adaptability of a species when they encounter changing environmental conditions. when an endangered species reduces, it loses genetic variation which may not be restored even if the species rebound and will only be recovered through the gradual collection of mutations over many years.