4. there are two categories of ultraviolet light. ultraviolet a (uva) has a wavelength ranging from 320 nm to 400 nm. it is not harmful to the skin and is necessary for the production of vitamin d. uvb, with a wavelength of 280 nm and 320 nm, is much more dangerous because it causes skin cancer. what are the frequency ranges for uva and uvb light?

real, smaller and upside-down.   so the answer should be b.

unlike poles attract

answer: the metamorphic rocks are formed when they are exposed to high pressure and high temperatures. this happens when one of the earth's plates comes in contact with the other plate by traveling in opposite directions, straight into each other or slipping under one another. the friction that is caused by this activity results in   melting of rocks and when it cools they are known as metamorphic rocks. this process needs a controlled amount of pressure and temperature otherwise it may turn into magma.