Can someone help me with my earth science homework please?

1) Ultraviolet.
2) Mostly because equatorial regions receive more solar radiation because of the angle between the sun and the earth. At higher latitudes the sun hits the Earth more obliquely which means solar radiation is more spread out by the time it reaches the ground and has to travel through more atmosphere so is also more attenuated.
3) Difficult to predict. If the axial tilt was less, more solar radiation would be received in winter at higher latitudes and less in summer. All other things being equal, that would mean cooler summers and warmer winters. However, this is grossly overly simplistic and the real climate system has too many feedbacks to say that would be the result.
4) Mostly the same reason as the equator is warm - the angle at which sunlight hits the Earth. Also polar areas are ice covered and dry. Ice reflects much of the solar energy the polar regions do receive back in to space. Low humidity means a locally reduced greenhouse effect (water vapour being the main greenhouse gas in the atmosphere). So, not only do polar regions get less energy, they are are poorer at retaining what energy they do receive.
5) Warmer and drier. Lower elevations are generally warmer, and warmer air can carry more moisture, so if the air warms, the humidity will drop.
6) Mostly the axial tilt. In the northern hemisphere summer, the north is angled towards the sun so receives more solar energy (at the same time the south points away and has its winter). As the earth moves around its orbit, the axial tilt causes the amount of energy the north receives to change, and six months later the north is angled away from the sun and has its winter (and the south which is now tilted towards the sun has its summer).
7) The equator receives most energy at the spring and autumn equinoxes - this is when the sun is directly overhead. At the (Northern hemisphere) summer solstice in June, d would be true.
8) Air expands as it warms and becomes less dense than colder air. This density difference drives convection.

That is a very thorough worksheet with good questions. The answers are all fairly obvious....IF you read the book!!! Sorry...not going to give you the answers. In the time you spent entering the question, you could have found a couple of the answers.