Organisms and their interactions:
* Animals: How do birds migrate? What are the social structures of wolf packs? How do insects pollinate plants?
* Plants: How do plants adapt to different environments? How do they reproduce? What are the medicinal properties of different plants?
* Microorganisms: How do bacteria cause disease? How can we use bacteria to break down pollution? How do viruses evolve?
* Ecosystems: How do different species interact within an ecosystem? How does human activity impact ecosystems? How can we conserve biodiversity?
Cellular and molecular biology:
* Genetics: How are traits inherited? How do mutations occur? How can we use genetic engineering to improve crops or treat disease?
* Cell biology: How do cells function? How do cells communicate with each other? How can we use cells to develop new therapies?
* Molecular biology: How do proteins fold? How do genes regulate protein production? How can we use our understanding of molecular biology to develop new drugs?
Evolution and diversity:
* Evolutionary history: How did life on Earth evolve? How do species adapt to their environment? What is the role of natural selection in evolution?
* Biodiversity: How many species are there on Earth? How are species related to each other? What are the threats to biodiversity?
Other areas:
* Biotechnology: How can we use living organisms to create new products or solve problems?
* Bioinformatics: How can we use computers to analyze biological data?
* Bioethics: What are the ethical implications of biological research?
This is just a small sample of what a biologist might study. The field is constantly evolving, and new areas of research are being explored all the time!