Vaccines are effective for LONG-TERM protection against diseases because vaccines stimulate _______ formation.
A. plasma-cell
B. antibody
C. memory-cell
D. T-cell
Answer: B. antibody
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The most species-rich groups of fungi are those with dikaryotic growth forms
Indicate whether the statement is true or false.
Why do aquatic plants frequently have broad, floating leaves?
a. The byproducts of photosynthesis, such as glucose, are naturally buoyant. b. Beneath a certain depth, insufficient oxygen exists to support photosynthesis. c. To maximize their opportunities for photosynthesis. d. Broad floating leaves provide shelter for fish that protect them from herbivores.
During translation, chain elongation continues until:
a) a stop codon is encountered. b) all the tRNAs are converted to mRNAs. c) all the tRNAs are enzymatically broken down. d) the ribosome falls off the end of the mRNA. e) all the amino acids in the cell are used up.
Which of the following situations would be MOST likely to produce a new species?
A. Several individuals join an existing population and introduce several new, beneficial alleles. B. A volcano erupts and kills all of the frogs on an island, along with many other species. New frogs colonize the island and begin reproducing rapidly because there are no longer any frog predators. C. A group of polyploid individuals arises by an abnormal meioses. The polyploids can only produce viable offspring by mating with each other. D. An existing species becomes subdivided by a glacier and the resulting groups remain physically isolated from each other for thousands of years. When the glacier melts, the two groups are able to interbreed. E. Several individuals colonize a new area and establish a population. Migration between the two populations is common.