Question

which statement best explains why bacteria are considered living organisms?
they are made of cells.
they are made up of biological macromolecules.
they can cause disease.
they contain organelles.
they move around.

Explanation:

To determine why bacteria are living organisms, we analyze each option:

• "They are made of cells": The cell is the basic unit of life. Bacteria are single - celled organisms, so being made of cells is a key characteristic of living things.
• "They are made up of biological macromolecules": Non - living things can also be made of biological macromolecules (e.g., a virus has macromolecules but is not considered fully living in the same way as cells), so this is not a defining feature of living organisms.
• "They can cause disease": Many non - living agents (like some toxins) can cause disease, so this is not a reason to be a living organism.
• "They contain organelles": Bacteria are prokaryotes and do not have membrane - bound organelles, so this is incorrect.
• "They move around": Some non - living things can move (e.g., dust particles in the wind), so movement alone is not a defining feature of life.

Answer:

A. They are made of cells