Yungoos evolves into Gumshoos at level 20, during the day. Rockruff will always evolve into Lycanroc, but the form depends on the game you're playing. Midday form appears in Sun, and Midnight form appears in Moon. Type: Null evolves into Silvally with high happiness.
Skeletal muscles are the muscles found in your legs and arms and throughout the body. The skeletal system is different from the smooth muscle system in organs like your liver and the cardiac muscle in your heart because the skeletal muscles contract voluntarily.
Every one of these activities uses up energy that must be replaced in part by taking in more oxygen. When you exercise, your muscles move more vigorously than when you are at rest. Their metabolic rate increases. They need more energy, so they produce more of the chemical energy molecule ATP. You need oxygen to produce ATP, so the more ATP you produce, the more oxygen your body requires.