What is one discovery made by a russian scientist that is the basis of medical research?

How are rocks that cooled within magma chambers found on earth’s surface today? they are pushed up by magma under earth’s surface. they are revealed by erosion of earth’s surface over time. they are pushed to earth’s surface because of their larger size. they are revealed at earth’s surface due to their low density.

In the diagram below, the northern hemisphere would be in what season at position a a.fall b. winter c.summer d.spring

Why do we perceive objects as retaining their brightness under different lighting levels?