CBSE Class 10 Answered

The ultimate mystery of whether the egg came first or the hen has been solved by the scientists recently. They claim that the hen came first and not the egg. Researchers found that the formation of egg shells relies on a protein found only in a hen’s ovaries. Therefore, an egg can exist only if it has been inside a hen. The protein called ovocledidin-17 or OC-17 acts as a catalyst to speed up the development of the shell. The protein converts calcium carbonate into calcite crystals which makes up the egg shell.This hard shell is essential to house the yolk and its protective fluids while the chick develops inside.