List the 2 major groups of biogenic sedimentary rocks based on their compositions.

Explanation:

Biogenic sedimentary rocks are formed by the remains of the animals and plants via the biological process .

The two major groups are as follows -

Limestone - lt is made up of the exoskeletons of the mollusk , reef-forming corals, and foraminiferans .

Coal - it is made from the carbon in the dead and buried organic material and the wood of the dead plants which do not decay ( due to lack of oxygen ) but get petrified over the time .