Biological particles are tiny structures that play essential roles in living organisms. They include components like cells, viruses, and organelles, which are the specialized parts within cells. These particles are crucial for various biological processes, such as reproduction, metabolism, and immune responses. These particles can vary in size and complexity. For example, viruses are much smaller than bacteria and can only replicate inside a host cell. In contrast, cells are the basic units of life, capable of performing all necessary functions to sustain an organism. Understanding biological particles helps scientists study health, disease, and the fundamental processes of life.