can be both an atom and a molecule. A) Hydrogen A) Helium

Hydrogen

Explanation:

Because helium is a noble gas with a full valence shell, it does not bond with other atoms readily. This means that it cannot be a molecule. However, hydrogen can bond with a lot of things, because of its unique property of having just one electron, meaning that it can donate or accept one, making it able to easily become a molecule. Hope this helps!

the electromagnetic spectrum includes, from longest wavelength to shortest: radio waves, microwaves, infrared, optical, ultraviolet, x-rays, and gamma-rays.

i think that d. wind is the answer.   i missed the question when i answered a. currents.