The smallest unit of biological structure that meets the functional requirements of “living” is the______. a. organ b. organelle c. cell d. macromolecule
The correct answer and explanation is:
The correct answer is c. cell.
A cell is the smallest unit of biological structure that meets all the functional requirements of life. It is the basic building block of all living organisms, from the simplest single-celled bacteria to complex multicellular plants and animals. Each cell carries out essential life processes such as metabolism, growth, reproduction, response to stimuli, and maintaining homeostasis.
Organs, listed as option a, are structures made up of multiple tissues working together to perform specific functions in an organism. Although organs are important for complex biological activities, they are composed of many cells and therefore are not the smallest functional unit of life.
Organelles, option b, are specialized structures within cells such as the nucleus, mitochondria, and ribosomes. Organelles carry out particular tasks within the cell, but on their own, they cannot perform all life functions independently. They depend on the cell’s overall structure and systems.
Macromolecules, option d, are large molecules like proteins, lipids, carbohydrates, and nucleic acids that make up the components of cells and organelles. While macromolecules are essential for biological processes, they are not considered living entities and cannot fulfill the criteria for life alone.
The cell is unique because it is the smallest unit capable of independently performing all activities necessary for life. It can process energy, synthesize molecules, reproduce by division, and respond to environmental changes. This makes the cell the fundamental unit of life in biology.