横向
1
Force that attracts objects together
4
Center of an atom or cell
5
Disturbance that transfers energy
6
Gas essential for breathing
8
Smallest unit of an element
纵向
2
Group of similar cells
3
Nerve cell in the brain
6
Path of a planet around the sun
7
Preserved remains of ancient life
9
Basic unit of life
10
Mass per unit volume