Which of these structures is a covering for the gill chamber in ray-finned fishes?
a. swim bladder
b. spiral valve
c. operculum
d. atrium
e. lateral-line system
C
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By examining the phylogenetic tree diagrammed in the figure above, what conclusion can you draw about the species G. microti?
A) It evolved before G. intestinalis. B) It is more closely related to G. muris than to G. intestinalis. C) It should not be labeled a species distinct from G. intestinalis. D) It is part of a monophyletic group that also includes G. intestinalis.
________ synthesis is a damage-tolerant mechanism that allows synthesis of a new DNA strand from a damaged template.
Fill in the blank(s) with the appropriate word(s).
The three main regions of the human small intestine proceeding in sequence from the stomach to the large intestine are
A. duodenum, ileum, and jejunum. B. ileum, duodenum, and jejunum. C. ileum, jejunum, and duodenum. D. jejunum, ileum, and duodenum. E. duodenum, jejunum, and ileum.
How many nucleotides form the code for one amino acid?
A. 2 D. 5 B. 3 E. 6 C. 4