横向
1
Mass per unit volume
3
Compound containing oxygen
5
Unit of force
7
Substance with pH above 7
9
The Red Planet
12
Form of thermal energy
13
Smallest unit of an element
纵向
2
Unit of energy
3
Gas essential for breathing
4
Glass that splits light into spectrum
6
Biological catalyst
8
Substance with pH below 7
10
Molten rock beneath Earth surface
11
Magnetic metallic element