Sponges have
A) an exoskeleton.
B) a gastrovascular cavity.
C) muscles.
D) spicules.
E) a nerve net.
D
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If the tight junctions in the intestine were disrupted _____
A. intestinal cells could not attach to the extracellular matrix. B. intestinal cells could not attach to integral membrane proteins. C. small molecules would not be exchanged between neighboring intestinal cells. D. bacteria could move from the intestines to the bloodstream causing an infection. E. small molecules would not be able to move into cells lining the intestine.
Drugs that are hepatotoxic cause damage to a patient's kidneys.
Answer the following statement true (T) or false (F)
The most ancient branching point in the phylogeny of animals is the one that distinguishes between having:
a. single cellularity and multicellularity. b. radial or bilateral symmetry. c. defined tissues or no tissues. d. growth by molting or by continuous additions. e. first gut opening develop into a mouth and first gut opening develop into an anus.
Which of the following observations provides the strongest evidence against root pressure being the principal mechanism of water transport in the xylem?
A) Not all soils have high concentrations of ions. B) Root pressure requires movement of water into the xylem from surrounding cells in the roots. C) Over long distances, the force of root pressure is not enough to overcome the force of gravity. D) There is no water potential gradient between roots and shoots.