Codons correspond to how many different amino acids?
a. 3
b. 9
c. 16
d. 20
e. 128
ANSWER: d
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A flower with petals, sepals, and one carpel but no stamens is ____
a. perfect and incomplete b. imperfect and complete c. imperfect and incomplete d. perfect and complete e. sterile
Lipids
a. yield less energy per gram than do carbohydrates. b. include cartilage and chitin. c. include fats consisting of one fatty-acid molecule and three glycerol molecules. d. are composed of monosaccharides. e. are none of these.
Which of the following statements best expresses the concept of punctuated equilibrium
A. Small variations gradually accumulate in evolving lineages over periods of millions of years B. Random mating ensures that the proportions of genotypes in a population remain unchanged from generation to generation C. Stability is achieved when selection favors the heterozygote, while both types of homozygotes are at a relative disadvantage D. Evolutionary changes consist of rapid bursts of speciation alternating with long periods which species remain essentially unmodified E. Under competition for identical resources, one of the two competing species will be eliminated or excluded
As a result of the long refractory period generated by __________, cardiac muscle can not exhibit __________.
A. the influx of calcium ions, tetanus (tetanic contractions) B. the out flow of K+, tetanus (tetanic contractions) C. the influx of Na+, tetanus (tetanic contractions) D. the influx of Ca++, recruitment E. the out flow of K+, recruitment