Fill in the word that correctly completes this sentence. A pure substance is a single kind of matter. (Word you fill in)
is made up of two or more substances that are together in the same place, but each substance keeps its own properties.

Great amounts of electromagnetic energy from our sun and other bodies in space travel through space. which is a logical conclusion about these electromagnetic waves? their energy must be very their frequency must be very low these waves can travel without a medium they only travel through a vacuum of space

Acontrol during an experiment. might change remains constant does not exist does change

If an atom has 12 protons and 13 neutrons