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 travel to the galciers is something one can never forget. The aura of the place along with the beauty that one gets to notice is so enriching to entice one to stay there forever. The glaciers are one of the many natural wonders our world has to offer. Formed because of the accumulation of the snow year after year, these glaciers are present in many sizes. Besides, the movement of the glaciers, such as the glacial erosion and deposition leads to the formation of many other attractive features, such as the corries, pyramidal peaks, truncated spurs, and hanging valleys. You must definitely visit these places to give your soul this exciting experience.
D: The reactions take place in the thylakoid of the chloroplast.
genetic drift
Explanation:
Genetic drift is changes in allele frequencies of a gene pool due to chance or random events. This can occur in large or small populations. Genetic drift causes gene pools of two isolated populations to become dissimilar as some alleles are lost and other are fixed.
