Cholesterol
The animal plasma membrane is a layer of phospholipids that is entwined with cholesterol and proteins. Cholesterol makes up a small part of the cell membrane's mass and it is present in every cell of the body. Cholesterol maintains the integrity of the cell membrane. It assists in the immobilization of the outer surface of the cell membrane and it reduces the permeability of the membrane to most biological molecules. Cholesterol also perform roles in cell signaling, maintaining fluidity and protecting important proteins in the membrane.
The term which describes any relationship in which two species live closely together is called SYMBIOSIS.
Answer:
The altitude of a triangle is the perpendicular line segment drawn from the vertex to the opposite side of the triangle. It may lie inside or outside the triangle, based on the types of triangles
Explanation:
for example look at the given picture