how do you think you can use lenses and mirrors to change the direction and intensity of a light wave?

Which of the following statements is not true? • a. covalent compounds have low melting and boiling points. • ob. covalent bonds between atoms of a compound are relatively weak compared to bonds between molecules. • c. covalent bonds occur between nonmetals. • d. covalent compounds are often gases or liquids.

1. list three scientific reasons cockroaches may fly.

Drug abuse will not lead to physical and psychological dependence. true or false ?