Without doing any calculations, determine the sign of δssys for each of the following chemical reactions.

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.

Earth takes in thermal energy from the sun in a process called . sunlight strikes earth’s surface at different angles. this angle is called the angle of . btw its

The structure of adenosine triphosphate (atp) is shown here. which statement best explains how energy stored in the chemical bonds of atp can be released.