B cells are more effective than macrophages in presenting antigens to activate T cells when
A. antigen concentrations are low.
B. macrophages are in short supply.
C. antigen concentrations are high.
D. None of the choices are correct.
Answer: A
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Macrocystis is the genus of kelp that dominates in:
a. the Indian Ocean. b. the North Atlantic. c. the Tropical Pacific. d. the Mediterranean. e. the Pacific Ocean.
A Barr body is an example of
A) constitutive euchromatin. B) facultative euchromatin. C) facultative heterochromatin. D) a nucleosome. E) constitutive heterochromatin.
Which phylum includes members that are considered by many researchers to be the living plants most closely related to the first land plants, based on morphology and mitochondrial gene sequence data?
a. Hepatophyta b. Bryophyta c. Pterophyta d. Anthocerophyta
Which of the following findings is a diagnostic criterion for monoclonal gammopathy of undetermined significance?
A. Serum monoclonal protein greater than 3 g/dL B. Plasma cell count lower than 10% of total cells in bone marrow C. Increased calcium in the blood D. Presence of CRAB features