which is true of a mechanical wave?

1. both sound and light are examples.
2. it can travel in a vacuum.
3. it must have a medium.
4. it must travel in empty space.

Plz choose one of the compounds from the table and explain how you know the numbers of atoms in your formula. is it possible for two different compounds to be made from the exact same two elements? why or why not? with a limited number of elements (less than 120 are known), does this mean we also have a small number of compounds or do we have a large number of compounds in this world?

Mitosis is a type of cell division that produces cells that are identical to the parent cell. meiosis is a different type of cell division that produces cells that carry have a genetic material of the parent cell. based on the information provided how do the purpose of mitosis and meiosis differ

What is the molar mass of potassium nitrate, kno3