Why is the plasma membrane called a selectively permeable membrane?
The plasma membrane allows or permits the entry and exists of some materials in and out of the cell. It also prevents movement of some other materials. The cell membrane, therefore, is called a selectively permeable membrane.
Explain various types of organisms on the basis of number of cells.
A, B, C and D are basic parts of all the cells. The part A contains thread like structures called E which transfer the characteristics from parents to their offsprings into the cell and out of the cell. The part B provides energy to the cell. The part C is found in plant cell but not in animal cell. The part D is a transparent, jelley–like material. What could A, B, C, D and E be?
In the organisation of a cell is destroyed due to some physical or chemical influence, what will happen?
What is an organ system?
(a) Give two examples of organ systems in animals.
(b) Name the two main organ systems in plants.
