At the end of chemical reactions, what is the total amount of the reactants compared to the total amount of the products?

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.

An example of a fine motor skill is

Aconstruction crew was made up of 88 men and the rest women. if 40% of the crew were men, how many people were in the crew?