This easy-level worksheet introduces second graders to two of the most familiar animal groups by asking them to sort dogs, cats, whales, lizards, snakes, and turtles into mammals or reptiles. Children then complete fill-in-the-blank sentences about fur, hair, dry scales, and how mammals feed their babies milk. A short true-or-false section checks basic facts, including whether fish breathe with lungs and whether snakes belong to the reptile group.