Why is there free oxygen in the air?
A. Organisms need oxygen to manufacture ATP.
B. Free oxygen has been present since the formation of the earth's atmosphere.
C. Evaporation of the oceans liberated oxygen.
D. It is a by-product of photosynthesis.
E. Free oxygen has seeped from cracks in the earth's crust.
D. It is a by-product of photosynthesis.
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A bacterial "bloom" is:
A. the reproductive parts of bacteria B. malformation of flowers caused by bacterial infections C. unusual coloring of the water of lakes, ponds, or the sea caused by high numbers of bacteria D. souring of milk caused by bacteria E. swelling of a wound because of bacterial infection
Four of the five processes listed below are functions
of the nephron. Select the exception. a. filtration b. dilution c. excretion d. reabsorption e. secretion
Which statement about van der Waal interactions is false?
a. They are very strong. b. They are attractive forces. c. They operate over very short distances. d. They form between nonpolar molecules. e. They involve transient regions of positive and negative charges.
Why are viruses called obligate intracellular parasites?
a) They must use a host cell's amino acids to synthesize proteins. b) They must use a host cell's nucleotides for transcription and replication. c) They must use a host cell's metabolic enzymes and pathways to obtain energy. d) They must use a host cell's ribosomes to synthesize proteins. e) All of the above.