That is what we call the muscular system. This system allows us to move, circulates blood through the body and their is 3 types of muscle. Skeletal muscle is voluntary and are mostly attached to two bones. Smooth muscle is found inside organs such as stomach and blood vessels. And Cardiac muscle is ONLY found in the heart .
The cause behind these changes is the that the temperature is changing while it is raining, so when it drops to 32 degrees F or below, it is snow. At 32 degrees F, it is sleet, and at higher than 32 degrees, it is going to be freezing rain.
It is intended to increase immunity against that antigen back to protective levels, after memory against that antigen has declined through time.
In Biology, a stimulus is a change in an organism's surroundings that causes the organism to change its behavior in order to make the environment more satisfactory.