横向
1
Substance with pH below 7
3
Unit of force
4
Mass per unit volume
8
Unit of energy
纵向
2
Compound containing oxygen
5
Smallest unit of an element
6
Ball of burning gas in space
7
Reddish electrical conductor
9
Basic unit of life
Substance with pH below 7
Unit of force
Mass per unit volume
Unit of energy
Compound containing oxygen
Smallest unit of an element
Ball of burning gas in space
Reddish electrical conductor
Basic unit of life