Answer:
A group of cells make a tissue, a group of tissues make and organ, a group of organs make an organ system, and an organ system makes a organism.
A person who specializes in the study of animals is called a zoologist. Zoologists who study certain kinds of animals have their own names.
<span>"Hypothesis, because tentative means unsure."
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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.