Question

select the correct description of elements.
all of these are correct.
particles within each atom that determine atomic mass
anything in the universe that takes up space
particles that cannot be broken down into other substances

Explanation:

Elements are substances made up of only one type of atom and cannot be broken down into simpler substances by chemical means. Particles within each atom that determine atomic mass are protons and neutrons, but this doesn't fully define elements. Anything in the universe that takes up space is matter in general, not just elements.

Answer:

particles that cannot be broken down into other substances