What is the main cause of extinction on earth today?

Because the earth is losing most of its habitats

Explanation:

Check with a teacher and ask its all science

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.