What is the basic unit of life?

What is the basic unit of life?

• A. Atom
• B. Molecule
• C. Organelle
• D. Cell

Answer: (D)

Cells are the basic units of life because they carry out all the processes that define living organisms. They perform metabolism, growth, response to stimuli, reproduction, and maintenance of internal conditions. Atoms and molecules are too small to carry out these life-sustaining activities on their own—they are the building blocks that make up matter and the molecules inside cells. Organelles are specialized structures within cells that perform particular tasks, but they cannot function independently outside a cell. In single-celled organisms, one cell does everything; in multicellular organisms, many cells work together to keep the organism alive. That combination of organization, function, and independence is why the cell is regarded as the basic unit of life.

Cells are the basic units of life because they carry out all the processes that define living organisms. They perform metabolism, growth, response to stimuli, reproduction, and maintenance of internal conditions. Atoms and molecules are too small to carry out these life-sustaining activities on their own—they are the building blocks that make up matter and the molecules inside cells. Organelles are specialized structures within cells that perform particular tasks, but they cannot function independently outside a cell. In single-celled organisms, one cell does everything; in multicellular organisms, many cells work together to keep the organism alive. That combination of organization, function, and independence is why the cell is regarded as the basic unit of life.