how are unicellular organisms considered living?

Unicellular organisms are considered living because they possess all the essential characteristics of life, including the ability to grow, reproduce, respond to stimuli, and carry out metabolic processes. They maintain homeostasis and can adapt to their environment, which are fundamental traits of living organisms. Despite being composed of a single cell, these organisms perform all necessary functions for survival independently. Examples include bacteria, protozoa, and some algae.