The trickling-filter system and the activated-sludge system both require
A) high levels of oxygen to promote aerobic decomposition.
B) high levels of carbon dioxide to adjust the pH of the water for bacterial action.
C) the addition of large amounts of chlorine to kill pathogens.
D) the addition of large amounts of ammonia as nutrients to support decomposers.
A
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Shallow wind-driven helical vortices are produced by ____________ ____________ with windows of convergences
where seaweed accumulates. Fill in the blank(s) with the appropriate word(s).
A student commented, "A metamorphic rock must have a greater relative age than a sedimentary rock." Is the student using the term "relative age" here in the correct context, and why or why not?
A) No. Relative age must compare the age of at least three things. B) Yes. The ages of the rocks are ordered in relation to each other. C) No. Relative age should state a specific number of years in which the event occurred. D) Yes, the term is used in the correct context, however knowing how long ago these types of rocks formed would be useful.
The three-cell model for general circulation:
A) includes a segment called the Hadley Cell. B) is a better representation of the atmosphere than the single-cell model. C) accounts for the positioning of the Polar and Subtropical jet streams. D) takes in to account the spin of the earth. E) all of the above
With regards to carbon monoxide (CO), which of the following is false?
A) Anthropogenic CO is principally produced by automobiles. B) Natural CO is produced by decaying organic debris, forest fires, or organic matter decomposition. C) Few effects of CO on humans have been identified. D) It is a colorless, odorless and tasteless gas.