And although you can't build from Planning Sets, they will allow you to gather bids from contractors, arrange your furniture in the plan, analyze traffic patterns and gauge the site lines on your lot.
A: Earth's atmosphere, which is around 300 miles thick, is mainly made of nitrogen and oxygen, although there are many other trace substances in its composition. Trace substances make up only 1 percent of the bulk of the atmosphere while nitrogen (78 percent), oxygen (21 percent) and argon (1 percent) make up the rest. Continue Reading
Roughly 71 percent of Earth's surface is covered by water, most of it in the oceans. About a fifth of Earth's atmosphere is made up of oxygen, produced by plants. While scientists have been studying our planet for centuries, much has been learned in recent decades by studying pictures of Earth from space.