A is the smallest structural and functional unit of life.

Question

A is the smallest structural and functional unit of life.

1. A. Blood
2. B. Bone
3. C. Sperm
4. D. Cell (Correct answer)

Correct Answer

Option D — Cell

Detailed Solution & Explanation

The correct answer is Cell.

Key Points

• The cell is the smallest structural and functional unit of life — the smallest entity that can carry out all the processes of living.
• Blood and bone are tissues made of many cells, and a sperm is one particular type of cell rather than the general unit.

Additional Information

• The cell theory, from Schleiden, Schwann and Virchow, holds that all living things are made of cells, the cell is the basic unit of life, and all cells arise from pre-existing cells.
• Robert Hooke first observed and named cells in 1665 while examining cork; Leeuwenhoek first saw living cells.
• The largest human cell is the ovum and the longest the nerve cell; the smallest known cells are Mycoplasma.