Questions: A bacterium that is pleomorphic is one that . divides in different ways exists in different shapes causes different diseases uses different energy sources

The answer is the second one: exists in different shapes.

Explanation for each option:

1. Divides in different ways: This is incorrect. Pleomorphism refers to the ability of an organism to alter its shape or size in response to environmental conditions, not the way it divides.
2. Exists in different shapes: This is correct. Pleomorphic bacteria can change their shape and size, which is a defining characteristic of pleomorphism.
3. Causes different diseases: This is incorrect. While pleomorphic bacteria might be involved in various diseases, pleomorphism itself refers to the variability in shape, not the range of diseases caused.
4. Uses different energy sources: This is incorrect. Pleomorphism does not relate to the metabolic pathways or energy sources used by the bacterium.

Summary: A pleomorphic bacterium is one that exists in different shapes.