As a part of the nitrogen cycle, animals acquire animo acids by doing which of the following?

By eating plants

Explanation:

The plants uptake the nitrogen by the help of the nitrogen fixing bacteria found in the soil. The nitrogen from the plants is taken by the animals eating the plants. The source of the nitrogen to the animals is the plants containing nitrogen. The plants are also supplied with some of the fertilizers that contains adequate amount of nitrogen in it, which is transferred to the animals when they eat it.