Susana heats up a sample of red crystals. While the sample is being heated, a gas is released and a blue powder is left after the heating. Is the sample of red crystals an element or a compound? Explain your answer.

Compound

Explanation:

Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions.Example: Copper

Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: water

Thus as it give that  the red sample on being heated, a gas is released and a blue powder is left after the heating. Thus the given sample is a compound.

the skeletons of most mammals reach a certain size and then stop growing. however, many animals, including some mammals, keep growing throughout their lives. kangaroos, for example, just keep growing and growing until they die. also, the longer an animal lives the greater the chance it might catch some deadly disease.