Why are bacteria needed in the nitrogen cycle?

Explanation: Bacteria are needed in the nitrogen cycle because plants and animals cannot directly use atmospheric nitrogen. Bacteria in the roots of plants trap nitrogen and convert it to ammonia and other nitrogen compounds which plants can then use to make protein

"a scientist studying a whale and its surroundings would need to understand the structure of atoms in case something was negatively affecting the whale or its surroundings."

explanation:

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b.have there own function.