Across
1
Natural satellite of Earth
4
Substance with pH above 7
5
Measure of matter in an object
6
Blocking of light by a celestial body
10
Second lightest element
11
Unit of force
12
Curved glass that refracts light
Down
2
Chemical element in table salt
3
Unit of heredity
5
Tissue that contracts for movement
7
Tectonic landmass section
8
Path of a planet around the sun
9
Gas essential for breathing