横向
1
Nerve cell in the brain
3
Basic unit of life
5
Gas essential for breathing
6
Naturally occurring inorganic solid
8
Infectious microscopic agent
纵向
2
Group of similar cells
3
Reddish electrical conductor
4
Compound containing oxygen
7
Element found in all living things
9
Ball of burning gas in space
10
Smallest unit of an element
11
Curved glass that refracts light
12
Center of an atom or cell