横向
1
Substance with pH below 7
4
Basic unit of life
5
Force that attracts objects together
6
Naturally occurring inorganic solid
9
Mass per unit volume
10
Measure of matter in an object
纵向
2
Compound containing oxygen
3
Solid with repeating atomic pattern
4
Reddish electrical conductor
7
Unit of heredity
8
Unit of force
11
Path of a planet around the sun
12
Group of similar cells