Adaptations-. Black bears have a thick layer of fur for the cold winters,claws to climb trees and stay away from danger along with sharp teeth for protection like scaring away predators and to tear apart fish.Bears also hibernate in the winter to avoid having to find food which is difficult in the winter.
The cell membrane, or plasma membrane, surrounds and protects the internal environment of a cell; however, this is not its only function. A cell membrane also determines what materials enter or leave the cell. This ensures that the cells will be able to get rid of wastes and take up important nutrients and gases.
Both eukaryotic cells, including plant cells and animal cells, and prokaryotic cells, e.g. bacteria, are enclosed by a cell membrane. A cell membrane (see the simple diagram on the right) is a thin structure that is also known as the plasma membrane.The main functions of the cell membrane are: The cell membrane forms a barrier between the inside of the cell and the environment outside the cell-enclosing cytoplasm and any organelles within the cell, and enabling different chemical environments to exist on each side of the cell membrane.