Final answer:
A nucleus is found in plant cells and is responsible for controlling the cell's activities and housing the DNA. Viruses, bacterial cells, and prokaryotes do not have a nucleus.
Step-by-step explanation:
A nucleus is a membrane-bound organelle found in eukaryotic cells, such as plant cells. It is the control center of the cell and houses the cell's genetic material, DNA. The nucleus is responsible for controlling the cell's activities and regulating gene expression.
In contrast, viruses, bacterial cells, and prokaryotes do not have a nucleus. Viruses lack cellular structures and genetic material, instead relying on the host cell's machinery for replication. Bacterial cells and prokaryotes have a nucleoid region that contains the DNA, but it is not enclosed within a membrane-bound nucleus.
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