What are the two main types of cells?

The two main types of cells are prokaryotic and eukaryotic. Prokaryotic cells are generally simpler and smaller, lacking a defined nucleus and membrane-bound organelles; they include bacteria and archaea. In contrast, eukaryotic cells are more complex, have a defined nucleus, and contain various membrane-bound organelles, which are characteristic of plants, animals, fungi, and protists.

Understanding this distinction is fundamental in biology, as it lays the groundwork for more complex concepts, including cellular processes, organism classification, and evolutionary biology. The other options represent different classifications or characteristics of cells rather than the primary types. For instance, animal and plant cells are both subsets of eukaryotic cells. Similarly, multicellular and unicellular describe the organization of living organisms rather than the cells themselves, while haploid and diploid are terms related to the number of chromosome sets in a cell.