Air enters human lungs from the mouth by passing through the ________.
A. posterior air sacs
B. trachea
C. spiracles
D. esophagus
E. nasal cavities
B. trachea
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While walking along the beach at Point Lobos, California, the fellow pictured walks up to you with algae in hand. Figuring you to be a college student who has probably had a good introductory biology course, he asks if you know what it is.
(a) What is the cell wall component of the organism that has commercial value? (b) Name three uses for that cell wall component.
With __________ growth, a small population starts growing slowly, then grows rapidly, and then levels off once __________ is reached.
Fill in the blank(s) with the appropriate word(s).
The transfer of genes during bacterial conjugation involves rigid, tubular appendages called
A. flagella. B. sex pili. C. periplasmic flagella (axial filaments). D. fimbriae. E. cilia.
How are most eukaryotic transcription regulators able to affect transcription when their binding sites are far from the promoter?
(a) by binding to their binding site and sliding to the site of RNA polymerase assembly (b) by looping out the intervening DNA between their binding site and the promoter (c) by unwinding the DNA between their binding site and the promoter (d) by attracting RNA polymerase and modifying it before it can bind to the promoter