Questions: How does a virus differ from a bacterium? Select all that apply. A virus, unlike a bacterium, lacks a genome. Viruses are two-dimensional, whereas bacteria are three-dimensional. Viruses, unlike bacteria, lack metabolic enzymes.

The correct answers are:

• Viruses, unlike bacteria, lack metabolic enzymes.

Explanation for each option:

1. A virus, unlike a bacterium, lacks a genome.
   This statement is incorrect. Both viruses and bacteria have genomes. Viruses have either DNA or RNA as their genetic material, while bacteria have DNA.

2. Viruses are two-dimensional, whereas bacteria are three-dimensional.
   This statement is incorrect. Both viruses and bacteria are three-dimensional structures. The description of viruses as two-dimensional is not accurate in the context of biological structures.

3. Viruses, unlike bacteria, lack metabolic enzymes.
   This statement is correct. Viruses do not have their own metabolic enzymes and rely on the host cell's machinery to replicate and perform metabolic functions. Bacteria, on the other hand, have their own metabolic enzymes and can carry out metabolic processes independently.

In summary, the key difference highlighted here is that viruses lack metabolic enzymes, which is a fundamental distinction from bacteria.