Which type of fossils are used to identify specific time periods?

if you know your abc's you should be able to get your answer or just use google

the correct answer is: " ventricles " .

{source: refer to text within question.}.

the flagellates share a facultative mutualist association with termites. mutualism is a biological interaction between individuals of different species, where both benefit from each other. this is called cooperation and it differs from other interactions such as cases of exploitation, such as parasitism, predation. in this interaction called association, both species cooperate and benefit.

i think your answer is a. it splits a cell into two new daughter cells. the others don't really make sense to me so i would go with that one.