Question

1. The monkey waved _______ fist against the glass and scared off the people who were watching. What pronoun goes in the blank? the one it's its

Answer 1

its. It's stands for it is.

Answer 2

The monkey waved its fist against the glass and scared off the people who were watching.

The other, it's, is a contraction. The two word put together are it is.

You wouldn't say; The monkey waved it is fist.

Hope this helps. :)