All cells are not equal in terms of number of shape, size, and numbers. Explain.
The shape and size of the cells depend on their ultimate function. In order to perform the vital functions, cells differ greatly in size, shape and number as follows:
Unicellular organisms are made up of just one cell (for example, bacteria, Amoeba) whereas multicellular organisms have many cells specialized for different functions (for example fungi, plants, animals)
The complex multicellular organisms have a large number of cells that are making up organ systems (for example gymnosperms, angiosperms, mammals) where simple multicellular organisms have less number of cells (for example Bryophytes, Pteridophytes, Poriferans, Platyhelminthes)
Nerve cells have to perform conduction of impulse so they are longer and branched at the ends. RBCs have to transport oxygen and have to travel within the blood vessels so they are biconcave. Parenchyma cells have to make up the ground tissue and store food so they are polygonal and round in shape.