Is the study of matter and energy ,and the interactions between the two through forces and motion

What is the number of moles of chemical units represented by 9.03x10^24? and how do i show work? (dumb it down )

Which is an example of a reversible physical change?

Choose the correct statement about licensed veterinarians in the united states. a. they must be certified by the avma. b. they can treat all nonhuman animals. c. they can can treat only animals specified on the license. d. they must choose a specialty.