Answer: animals
Step-by-step explanation:
Field communities may be near rivers. Some fields have been made into pastures where animals graze.
Explanation: In this sentence, the word "graze" refers to the act of animals feeding on grass and other plants in a pasture. Pastures are typically fields that have been converted from agricultural land to land for animal grazing. The fields near rivers are likely to be converted into pastures due to the availability of water for the animals.