横向
1
Our home planet
4
Substance with pH below 7
5
Gas essential for breathing
6
Group of similar cells
9
The Red Planet
纵向
2
Smallest unit of an element
3
Blocking of light by a celestial body
7
Natural satellite of Earth
8
Unit of heredity
Our home planet
Substance with pH below 7
Gas essential for breathing
Group of similar cells
The Red Planet
Smallest unit of an element
Blocking of light by a celestial body
Natural satellite of Earth
Unit of heredity