Across
1
Reddish electrical conductor
3
Absolute temperature scale unit
4
Measure of matter in an object
7
Gas essential for breathing
8
Force that attracts objects together
9
Center of an atom or cell
11
Icy body with a tail near the sun
Down
1
Element found in all living things
2
Naturally occurring inorganic solid
5
Chemical element in table salt
6
Group of similar cells
10
Curved glass that refracts light