Self-reactive B cells are removed during embryonic development in the bone marrow through a process referred to as ________ selection.
A. ablative
B. positive
C. negative
D. clonal
Answer: C
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A temperate phage
A. may be lysogenic. B. may be lytic. C. enters a lysogenic or lytic life cycle shortly after entering the host cell. D. are all RNA viruses. E. may be lysogenic AND enters a lysogenic or lytic life cycle shortly after entering the host cell.
This phylum of nonvascular plants has about 10,000 known living species, including those in the
genus Sphagnum, a peat moss used by humans for its absorbent property and also as a fuel.
a. Hepatophyta b. Pterophyta c. Bryophyta d. Lycophyta e. Anthocerophyta
Which of the following best describes mollusks?
A. They are bilaterally symmetrical and have a soft body always covered with a shell. B. They have radial body symmetry and a soft body always covered with a shell. C. They have radial body symmetry and a soft body sometimes covered with a shell. D. They are bilaterally symmetrical and have a soft body sometimes covered with a shell.
________ are physical or chemical agents that cause mutation.
Fill in the blank(s) with the appropriate word(s).