A student is designing a device that can be used for communication. Which TWO waves on the electromagnetic spectrum should the student use?

gamma rays

X-rays

ultraviolet waves

microwaves

radio waves

Compounds like CCl₂F₂ are known as chlorofluorocarbons, or CFCs. These compounds were once widely used as refrigerants but are now being replaced by compounds that are believed to be less harmful to the environment.

Which best describes the transition from gas to liquid? Energy must be removed because particles in liquid move more slowly. Energy must be added because particles in liquid move more quickly.

If a neutral atom loses 2 electrons, what will happen to the atom's electrical charge?. A. it will become positive. B. it will become negative. C. it will remain neutral

What would happen if the cell cycle stopped in a multicellular organism

The elements in group 2 all have _ valence electrons. A. 2 4 6 8

Which best describes thermal energy? It is the difference between internal energies of two or more substances It is the sum of internal energies of two or more substances O It is the portion of internal energy that can be transferred from one

According to Neil's Bohr's atomic model, what occurs when an atom absorbs radiated energy? A) an electron shifts from a lower energy to a higher one B) an electron shifts from a higher energy lever to a lower one C) an electron spirals towards the

Which is true about dissolving a polar substance in water? A) the solvent particles are all nonpolar molecules B) the solute particles are carried into the solution C) the solute particles have no attraction for the solvent molecules D) the solute

Which societal problem can be solved, in part, by scientists identifying areas of high biodiversity? A. reducing the amount of pollution B. finding affordable housing C. protecting the environment D. providing access to clean water

Brianna wanted to compare the densities of two different solids of the same size 6cm3 (same volume) to see which one was more dense. Solid A had a mass of 2 grams and Solid B had a mass of 0.5 grams.