Why couple use a method of birth control

because it will control the birth of a child which can happen alot being overpopulated in the country or world. It also can mange their life and create a small and happy and healthy family.Also the child can get more love and support from their parents if they have less children and it wont be a taruma for the couple as well.  because growing a child can be expensive time costly and really hard.  

plz mark me as a brainlest a and thanks my answer

Explanation:

and btw i think the subject should be biology not chemestry

c- cold periods in earth's history during which glaciers covered much of the surface.

explanation:

the answer is definitely c.