Scientists measured the pressure in the xylem of redwood trees at different heights and found that the higher they made their measurements, the lower the pressure. They extrapolated this to a pressure of zero, and concluded that the tallest a tree could grow is 122-130 meters. The tallest know tree on Earth is 112.7 meters. Which of the following most likely limits the height of trees?
A. the amount of transpiration in leaves
B. the amount of photosynthesis in leaves
C. the amount of energy needed to pump water to the tops of the trees
D. the strength of water cohesion
E. the ability to take up CO2
Ans: D. the strength of water cohesion
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There are more helpful types of bacteria on this planet than harmful types.
Indicate whether the statement is true or false.
Insertions and deletions of three base pairs:
A. change one codon and, therefore, only one amino acid in the protein sequence. B. do not disrupt the reading frame so the protein ends up completely normal. C. do not disrupt the reading frame so the protein will usually retain some degree of function. D. cause frameshifts that will change the reading frame and, therefore, the sequence of the protein. E. usually result in the expression of a truncated protein.
Which of the following statements best describes the habitats of Achromobacter, Alcaligenes, and Bordetella?
a. The habitats are limited to the upper res-piratory tract of various mammals. b. The habitats vary from the soil and water environment to the upper respiratory tract of various mammals. c. The habitats are limited to the soil and water environment. d. The habitats are limited to the mucous membranes of humans and animals.
Glycolysis breaks down glucose into two pyruvates.
a. true b. false