How and why of exercise

Swimming is one of the most efficient exercises. This book instructs readers on proper technique and teaches them what processes occur within the body during exercise.

The main thing that contractions and possessives have in common is that they both use apostrophes. This handy primer explains how to use and form both. It also addresses the common confusion between "it's" and "its." Exercises with explained answers reinforce the skills taught. A great way to teach a key topic in the Common Core Language Standards! CCSS.ELA-Literacy. L.3.2, 2d, 3.