The hypothesis that high pressure forces phloem sap to flow was tested and supported by studies using

a. caterpillars.
b. radiolabeled hormones.
c. vacuum chambers.
d. aphids.
e. radiolabeled sugars.


D

Biology & Microbiology

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Which of the following plant structures shares the most common features and functions with a fungal hyphae?

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The adenylation of DNA ligase is:

A. an unstable initial step in the reaction. B. occurs at a lysine residue in the DNA binding domain. C. dependent on the presence of DNA. D. independent of the presence of DNA. E. more efficient at lower pH.

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Semen contains

a. sperm. b. the secretions of sex accessory glands. c. eggs. d. both a and b.

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Four of the following are extraembryonic membranes of the amniote egg. Which one is the exception?

a. albumen b. amnion c. chorion d. allantois e. yolk sac

Biology & Microbiology