The answer is Physical Property
In the deep layers of the ocean, various distinct kinds of species are found like fangtooth fish and vampire squid, to sea urchins and coffinfish.
One of the probable adaptation, which is not fully understood in the deep sea is gigantism. This refers to the ability of animals to become highly enormous in size. A well-known illustration is a giant squid, and others, like giant isopod, the kings of herrings selfish, and the colossal squid.
One of the possible reason of gigantism is the tendency of the species in the deep sea to live for long years, that is, for decades or for even centuries. As food is not abundant in the deep zones, thus deep sea creatures have evolved some interesting mechanisms of feeding.
In the non-existence of photosynthesis, the majority of food comprises of detritus, that is, the decaying leftovers of algae, microbes, animals, and plants from the upper layers of the ocean. Apart from that, the corpses of large animals, like whales that sink to the bottom give irregular but huge feasts for deep-sea animals.
Endocrine gland - a group of cells that secretes substances into the blood or directly into an organ.
Differ from exocrine glands, endocrine glands have no ducts and secrete products (hormones) directly into blood.
Hormone - a substance produced by cells that helps specific groups of cells to perform specific functions. It is a product of endocrine gland which functions as chemical messengers to stimulate other cells.
Duct – a channel or tube that conveys a substance. It is part of the exocrine glands (such as salivary glands) which makes contact with surface .
I believe the correct answer is a. mutations.
