横向
1
Magnetic metallic element
4
The Red Planet
6
Unit of heredity
8
Substance with pH above 7
9
Mass per unit volume
10
Disturbance that transfers energy
11
Smallest unit of an element
纵向
2
Group of similar cells
3
Path of a planet around the sun
5
Positive particle in nucleus
7
Naturally occurring inorganic solid
12
Ball of burning gas in space
13
Molten rock beneath Earth surface