EVERYDAY SCIENCE

Detailed explanation-1: -All the life processes in a unicellular organism, including digestion, excretion, respiration, occur within a single cell. These cannot be seen by naked eyes and are hence called microorganisms. There are several kinds of unicellular organisms such as bacteria, protozoa, algae, fungi, etc.

Detailed explanation-2: -When all the vital functions which are necessary for life are performed by a single cell then such cell is called the unicellular organism. Some examples of unicellular organisms are Amoeba, Paramecium etc. Bacteria are also unicellular organisms.

Detailed explanation-3: -Microorganisms can be unicellular (single cell), multicellular (cell colony), or acellular (lacking cells). They include bacteria, archaea, fungi, protozoa, algae, and viruses. Bacteria are single celled microbes that lack a nucleus. Archaea are like bacteria, but they have different structures and properties.

Detailed explanation-4: -A bacterium, though, is alive. Although it is a single cell, it can generate energy and the molecules needed to sustain itself, and it can reproduce.