Why does the illumination of the moons surface appear to change when viewed from earth even through the sun continuously illuminates half of the moon?

The revolution of the Moon around the Earth makes the Moon appear as if it is changing shape in the sky. This is caused by the different angles from which we see the bright part of the Moon's surface. These are called "phases" of the Moon.

Explanation:

an adaptation is a change or process by which an organism takes to be better suited for its environment. for example; migration is a behavioral adaptation, this is needed because birds are not built to last extremely cold climates. there are different adaptations because there are different species needing to adjust to different things, bears don't migrate; they hibernate.

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.