Answer is terminology. (It’s the third word ending in gry. Usin(g) popula(r) teminolog(y)

He said: I finished it. You see, there is a goat. Goats eat grass so the goat in my picture ate the grass. Now the grass is gone. But since there is no more grass left, the goat went somewhere else to find more grass to eat. That’s why the homework is blank.