A. 5%
B. 10%
C. 20%
D. 60%
Ecology
Ecology
A. biogeochemical cycle
B. carboncycle
C. recycle
D. none
A. sand
B. mud
C. water
D. carbon dioxide
A. bug
B. echinoderm
C. fish
D. reptiles
A. 2 billion
B. 3 billion
C. 6.1 billion
D. 7 billion
A. age structure
B. community
C. population growth
D. observation
A. pollution
B. snow falling
C. storm
D. rain
A. green house effect
B. acid produce
C. air fresh
D. acid rain
A. ozone
B. oxygen
C. carbon
D. nitrogen
A. biological maginfication
B. pollution
C. succession
D. community
