Answer:
Every living organism is made up of cell or cells. Hence, cells are known to be the basic unit and characteristic of life. All organisms need certain characteristics to survive such as air, energy and water. Oxygen is required by almost every living organism to breathe. Carbon dioxide is essential for plants as they will not be able to carry out photosynthesis without it. Nitrogen is also essential for the building of macromolecules like amino acids by the living cells.
