Which of the following steps in the nitrogen cycle takes place after animals eat plants? A) Decaying waste returns nitrogen to the soil.
B) Bacteria on plant roots fix nitrogen to make it usable.
C) Plants use nitrogen from the soil.
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O D) Lightning changes nitrogen gas into nitrogen compounds.

A. Decaying waste returns nitrogen to the soil.

Explanation:

Hopefully this helps

thinking it would be d not too sure but i think it's right

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.