A muscle in the upper arm that extends (straightens) the arm. The smallest biological structural units of the body: There are different kinds of cells in your body that each do a specific job. are made of different kinds of tissues that work together.
A. Would be the answer I chose.
It said one of the following WORKOUT CHANGES, so I'm assuming that it doesn't want you to just stop. Different shoes may provide better support, bringing relief to the knees and allowing you to continue your walking workout.
Your answer would be proteins.
