Resistance of some animals to certain viral diseases is based on
A. lack of spikes for attachment.
B. phagocytosis of the virus by the host cell.
C. the presence of the viral envelope.
D. lack of specific receptors on the host cell.
D
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Consider Mendel's experiments involving the trait of round versus wrinkled peas
In some experiments, Mendel's method involved removing the anthers that produce pollen from the flowers of the round peas and applying pollen from the anthers of the wrinkled plant. What would have happened if Mendel had missed some anthers he was trying to remove from the flowers of the plants that produce only round peas, and observed the peas produced by a plant that had a mix of round and wrinkled pollen? (Indicate which of the following MUST be true.) Comments: This problem is more complicated that it might appear at first. For example, if the parent with some of its own anthers and some introduced pollen has a phenotype that results from a homozygous dominant genotype, the F1 would all appear to have the dominant phenotype even if some recessive pollen grains were introduced. However, if the parent had a recessive phenotype and mixed pollen, the results would differ. Remember, the 9:3:3:1 ratio is when two different genes are involved. A. The F1 peas produced would have mixed phenotypes. B. The F1 peas produced would have a single phenotype. C. The F2 peas would have phenotypes in a 9:3:3:1 ratio. D. The F2 peas would all have the phenotype of the parental plant with the anthers not properly removed. E. The F1 peas would have phenotypes in a 1:1 ratio.
Lakes with elevated dissolved nutrients and low water clarity are called
A. lotic. B. oligotrophic. C. eutrophic. D. pelagic. E. photic.
The most serious threat to biodiversity is habitat destruction
Indicate whether the statement is true or false
The two hormones involved in seed germination and seed dormancy are
A) auxin and ethylene. B) gibberellin and auxin. C) ethylene and cytokinin. D) abscisic acid and gibberellin. E) cytokinin and auxin.