How many mass extinctions mark the boundaries for geologic time periods?

A. One
B. Three
C. Five
D. Eight
E. Twelve


Answer: C

Biology & Microbiology

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Gene transfer that requires cell-to-cell contact is

A. transformation. B. competency. C. conjugation. D. functional genomics

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Which of the following is not true of Streptococcus pneumoniae?

A. It produces an alpha-hemolysin and hydrogen peroxide. B. It has a polysaccharide capsule that resists phagocytosis. C. It is a small, gram-negative coccus. D. It is the most frequent cause of community-acquired meningitis.

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Some nerves are myelinated, and others are not. Myelinated nerves send signals faster than unmyelinated neurons. Draw two neurons of equal length, and wrap segments of myelin along one. Be careful to leave spaces for the nodes of Ranvier

Now, measure the exposed axons of each, and total up the distance. Describe why the myelinated neurons send signals faster.

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3 checkpoints of the cell cycle

What will be an ideal response?

Biology & Microbiology