Question

fix the two words that are used incorrectly.
whales are mammals, not fish. they breath using lungs, not gills, and
their warm - blooded.

Explanation:

1. "breath" is a noun; the correct verb form for the action of taking in air is "breathe".
2. "their" is a possessive pronoun, but here we need the contraction "they're" (they are) to describe that whales are warm - blooded.

Answer:

The two incorrect words are "breath" (should be "breathe") and "their" (should be "they're").