Across
1
Substance with pH above 7
2
Force that attracts objects together
4
Disturbance that transfers energy
6
Natural satellite of Earth
7
Icy body with a tail near the sun
10
Positive particle in nucleus
Down
2
Unit of heredity
3
Amplified beam of light
5
Chemical element in table salt
7
Element found in all living things
8
Gas essential for breathing
9
Gas form of a liquid