The correct answer would be
C.) <span>Polio Vaccination.</span>
I think the answer may be D. But don’t answer yet, I may be wrong.
The correct answer is an accumulation of microorganisms in deep marine environments.
Chalk rock refers to a pure form of limestone produced in tropical and warm seas about 100 million years ago in the Cretaceous period. The microscopic marine algae known as coccoliths thrived in the ancient seas. Their shells were comprised of calcite. With the death of the algae, their bodies sunk to the floor of the sea and sediment of chalk got deposited.
Over many years layers of chalk sediment got deposited and resulted in compaction of loose sediment into solid chalk rock.
The structure of DNA is double helix which looks like twisted ladder. The sides of the DNA molecule, the rails of the ladder are composed of alternate phosphate and sugar molecules.
The cell is most likely prokaryotic because:
Prokaryotes lack membrane-bound organelles such as the nucleus due to which the DNA are seen throughout the cytoplasm.
Eukaryotes have membrane-bound organelles such as the nucleus. So for eukaryotes, the DNA will be present packed inside the nucleus instead of being dispersed in the cytoplasm.
Prokaryotes can either be autotrophic or heterotrophic depending on their mode of nutrition. Autotrophic prokaryotes can make organic molecules for a carbon dioxide source. On the other hand, heterotrophic prokaryotes can take carbon from organic compounds. Hence, the organism can be autotrophic or heterotrophic.