The correct answer is D. The theory of natural selection provided a better explanation of the processes that were being observed by the scientists.They observed that the related species birds found on one island were slightly different from that of the other, and certain portions earth, have the species, which were not found anywhere else.
If you were studying climate change in general. The answer would be the last one which is ecosystem because it’s the study of the environment
Answer:
Part of the extracellular matrix secreted by osteocytes. (Ans. B)
Explanation:
Cells which are present on bones are known as osteocytes. Bone is composed of extracellular matrix, and cells. There are three types of cells which are present in the bones:
1) Osteoprogenitor cells.
2) Osteoblast.
3) Osteocyte.
Extracellular matrix is composed of organic matrix consisting glycoproteins, proteoglycans, osteocalcin also known as calcium binding proteins, and osteonectin which anchors bone mineral to collagen.
Meiosis is the cell division in which there is a formation of chiasmata......which lead to variation......
Marine birds or aquatic birds secrete a greasy oily substance that is mainly composed of quite unusual lipids. These birds have an organ called a preen gland also uropygial gland located at the back near the base of the tail that is responsible for the secretion of this substance.
The birds apply this oily substance over their feathers by rubbing their bill and head over the uropygial gland then rubbing off the accumulated oil quite thoroughly over the feathers of wings, back and every accessible part including the skin of their legs and feet.
This oil produces a waterproofing effect on the birds' feathers and thus they do not get wet but water simply runs off their surface.
