Oxygen first began to accumulate in Earth's atmosphere as a result of ____
A) biosynthesis
B) cellular respiration
C) methane synthesis
D) photosynthesis
D
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Match water-cycle terms that are most closely related.
- Infiltration
- Melt Water
- Precipitation
- Runoff
- Transpiration
- Water Vapor
Group B:
- Gas
- Groundwater
- Ice
- Plants
- Rainfall
- Stream
We deal with toxic substances every day. All of the following are methods used to limit risk from exposure to toxic substances EXCEPT
A. establishing a level (threshold level) below which exposed test animals show no reaction. B. setting limits to the amount of exposure a person is allowed to receive in the workplace. C. subjecting test animals to a substance to see if they become ill or die. D. prohibiting the use of toxic substances by the public.
What mountain range in Europe is over 500 miles long and has peaks reaching 15,000 feet?
A) Pyrenees B) Alps C) Carpathians D) Himalayas E) Apennines
____________________ ____________________ ____________________ consisting of ice and frozen nitrogen compounds form over Antarctica in June
Fill in the blank(s) with correct word