Which pure substance is made of only one kind of atom?
a. an element
b. am electron
c. a particle
d. a proton

What best discribes the relationship between wavelength and frequency in a electromagnetic wave

Which property of a rock remains unchanged by mechanical weathering? a. total surface area b. size and shape c. mineral composition d. sharpness

Witch two conditions can limit the usefulness of the kinetic molecular theory in describing gas behavior?