Nearly 300 million years ago, dragonflies existed that were the size of large hawks today. Some scientists believe that these giants could fly then, but not today, because oxygen levels in the atmosphere were much greater
If oxygen levels 300 million years ago were 50% higher than today, what percentage of the atmosphere would have consisted of oxygen for these giant dragonflies? A) 30%
B) 20%
C) 10%
D) 2%
A
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Hurricanes are to warm, moist water as earthquakes are to
A. blocks of deformed rock. B. tsunami. C. volcanoes. D. mountains.
The half-life of radioactive parent isotope Q is 500 million years. Scientists testing a rock sample discover that the sample contains an equal number of daughter and parent isotopes. What is the age of the rock?
- 500 million
- 1000 million
- 1500 million
- 2000 million
A cell value of zero in a flow accumulation raster indicates that the cell is located on a:
A. ridge B. flat area C. stream
One primary environmental condition that determines the success of an organism.
A. denitrifying bacteria B. herbivore C. omnivore D. producer E. trophic level F. community G. ectoparasite H. limiting factor I. secondary consumer J. nitrogen cycle K. biomass L. habitat M. carbon cycle N. interspecific competition O. nitrogen-fixing bacteria P. intraspecific competition