Answer:
The earth's crust represents the extreme outer, hard layer of the earth. It is made up of lithospheric plates that are of 2 types, namely the continental and the oceanic plate. The continental crust is thick and less dense, mainly comprised of granitic rocks with an abundance of silicate minerals and feldspars. Whereas the oceanic crust is dense and less thicker, mainly comprised of basaltic rocks.
The continental crust includes the total landmass and the oceanic crust includes the total water bodies on earth. The earth is covered with about 70% of the water bodies and only 30% of landmass. There are 5 major oceans on earth and are namely the Pacific, the Atlantic, the Indian, the Antarctic and the Arctic. The size of these oceans is enormous, where the Pacific is the biggest, having a total area of approximately 62.5 million square miles and the Arctic ocean is the smallest, having an area of about 5.5 million square miles.
These oceans are present over the oceanic crust and their size increases or decrease depending upon the type of plate boundary it forms. For example, the Pacific ocean is rapidly shrinking due as it sinks below the adjacent continental plates on the northern, eastern and western directions, sharing a convergent plate boundary. Whereas the Atlantic ocean is spreading and increasing in size as seafloor spreading takes place along the mid-oceanic ridge due to the sharing of a divergent plate boundary. Thus, due to the plate motion or movement of these crusts, the size of the plate increases or decreases.
