Which of the following statements about the immune system is correct?
a. Memory cells are involved in a primary immune response.
b. Dendritic cells were first identified in the nervous system.
c. Interferons are specific proteins that block cell replication at the level of mitosis.
d. Natural killer cells are involved in both specific and nonspecific immune responses.
e. Defensins are one type of protective protein synthesized by T helper cells.
D
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Interactions that keep the conditions in the body's internal environment within tolerable limits are collectively referred to as ________
a. metabolism b. homeostasis c. physiology d. development
Sensory adaptation
a. increases one's sensitivity to changes in environmental stimuli. b. increases one's sensitivity to constant stimuli. c. is primarily associated with pain receptors. d. functions the same way in all types of sensory receptors. e. is unique to predator animals.
White fruit color in summer squash is influenced by a dominant allele W, whereas colored fruit must be ww. In the
presence of ww, a dominant gene G results in yellow fruit, and homozygous gg results in green fruit. Give the F2 phenotypic ratios resulting from a cross of a true-breeding plant with white fruit (genotype WW GG) with a plant with green fruit. What will be an ideal response?
The movement of water through a membrane is dependent on
a. the concentration of solute. b. channel proteins. c. the extent of packing of the phospholipids. d. active transport. e. endocytosis.