The terrestrial planets are closer to the sun, they are smaller that the jovian planets, they have less moons, and do not have a lot of gases on the surfaces. The jovian planets are farther away from the sun, they are much bigger than the terrestrial planets, have a lot of moons, at least two planets are gas giants, and at least two have rings, and they have more gases. Temperatures can be a difference too.
Author is the person who wrote or created the original work. Journal articles are used by most fields to publish their original findings. These documents are regarded as primary sources.
i can only give an answer to number 1.
land. because most disasters that occur are caused by either air or water. air pollution or flood.
