if you hold your arm outstretched with palm upward, the force to keep your arm from falling comes from your deltoid muscle. assume that the arm has mass 4.0 kg and the distances and angles shown in (figure 1).

Remote sensing of the earth's surface and atmosphere may involve the use of what type of instruments?

Earth's atmosphere is unique among the planets and is able to support life because it contains a large amount of a) oxygen b) helium c) methane d) carbon dioxide

In the image, layer a is the topmost layer. layer c contains fossils from the precambrian era. layer b contains dinosaur fossils, and layer a contains fossils of mammals. which two statements are supported by this evidence? 1. mammals lived before the precambrian era. 2. dinosaurs and mammals existed in the precambrian era. 3. dinosaurs evolved after precambrian organisms. 4. precambrian organisms evolved after dinosaurs. 5. precambrian organisms were the first life-forms to become fossilized, according to this sample.