Correct sentence: The kiang eats tough grasses and roots it finds among the rocks.
Simple version for you: The kiang eats tough grass and roots near the rocks.
Why this is correct (very simple):
- The kiang = the animal we are talking about (the subject).
- eats = a simple word that means the same as "feasts on" and is easier to understand.
- it finds = "it" means the kiang; this tells us the food is what the kiang finds.
- among the rocks = tells where the food is.
Both the original and the corrected sentence are grammatically okay; the changes just make the sentence a little clearer for a young reader.