NEET BIOLOGY

Detailed explanation-1: -The increase in size and changes in shape of a developing organism depend on the increase in the number and size of cells that make up the individual. Increase in cell number occurs by a precise cellular reproductive mechanism called mitosis.

Detailed explanation-2: -Body tissues grow by increasing the number of cells that make them up. Cells in many tissues in the body divide and grow very quickly until we become adults. When we are adults many cells mature and become specialised for their particular job in the body.

Detailed explanation-3: -The process of increasing the number of cells, applied for growth and various other activities in the body, by division of older cells to form new cells, is termed as Cell division.

Detailed explanation-4: -In general, we grow to our full adult size via an increase in the number-not the size-of our cells. But some of our cells can change size-and this can be for healthy or not-so-healthy reasons.

Detailed explanation-5: -The correct option is D. Growth. Growth is the most obvious sign of life in organisms. Growth is an irreversible permanent increase in size due to an increase in the mass of the cells, that is increase in cell protoplasm, and an increase in the number of cells, that is by cell division.