4. The particles inside the nucleus are the
and

The heliocentric and the geocentric models of the solar system included these central principles

Name two kinds of practical electric pumps.

Which statement is the best definition of an atom? a) anything that has mass and occupies space. b) the smallest particle that has the properties of an element. c) a substance that cannot be broken down chemically into simpler substances. eliminate d) the smallest unit of a substance that exhibits all of the properties characteristic of that substance.