A biologist is a scientist who studies living organisms and their interactions with the environment. There are many different branches and subfields of biology, such as biochemistry, molecular biology, ecology, genetics, microbiology, zoology, botany, and more.
A biologist might choose to study a variety of topics, such as:
1: The structure and function of cells, molecules, and macromolecules.
2: The processes and mechanisms of life, such as metabolism, reproduction, and evolution.
3: The diversity and classification of living organisms, from bacteria to plants to animals.
4: The relationships and interactions between organisms and their habitats, such as food webs, symbiosis, and biogeochemical cycles.
5: The effects of environmental factors and human activities on biological systems, such as pollution, climate change, and conservation.
These are just some of the many possible topics that a biologist might choose to study.