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#Question id: 13142

The Norway rat (Rattus Norvegicus), a widespread pest, was controlled for about a decade by the anticoagulant warfarin. This chemical substance, placed in food pellets, is absorbed by the intestinal tract and inhibits the clotting of blood. After a population decline for about 10 years, rat populations increased and stabilized. In one European population, as illustrated in the graph below, the percentage of rats resistant to warfarin has remained fairly stable over a number of years.

Resistance to warfarin is governed by a dominant autosomal gene, R. More than 15 percent of the resistant animals are heterozygous at this locus (Rr). The table below indicates the response to warfarin and relative reproductive fitness of individuals that are homozygous or heterozygous for the dominant gene (R). The RR individuals have a 20-fold increase in vitamin K requirement over individuals.

Fitness is a measure of the reproductive success of a particular genotype. The highest fitness is 1.00.
There is a substantial number of heterozygotes in the population. Which of the following is the best explanation of this observation?

#Unit 10. Ecological Principles
  1. Heterozygotes (Rr) have a selective advantage over both homozygotes (RR and rr). 
  2. The gene for susceptibility (r) is increasing rapidly each generation.
  3. The gene for susceptibility (r) is being lost by chance each generation.
  4. Dominant homozygotes (RR) enjoy a reproductive advantage over heterozygotes
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TLS Online TPP Program

#Question id: 19357

#Unit 13. Methods in Biology

BAC vectors are based on _________ plasmid.
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#Question id: 9280

#Unit 6. System Physiology – Plant

Oxygen-Evolving Organisms Have two Photosystems that Operate in Series, explain by emerson that is the Photosystem I preferentially absorbs far-red light of wavelengths greater than 680 nm; photosystem II preferentially absorbs red light of 680 nm and is driven very poorly by far-red light; Another difference between the photosystems is that,

a.) Photosystem I produces a strong reductant, capable of reducing NADP+, and a weak oxidant

b.) Photosystem I produces a very strong oxidant, capable of oxidizing water, and a weaker reductant than the one produced by photosystem II

c.) Photosystem II produces a strong reductant, capable of reducing NADP+, and a weak oxidant

d.) Photosystem II produces a very strong oxidant, capable of oxidizing water, and a weaker reductant than the one produced by photosystem I

Which statements would be CORRECT?
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#Question id: 19696

#Unit 13. Methods in Biology

Different leads are used to record ECG of humans. Which of the following connection shows in recording limb lead I?
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#Question id: 11162

#Unit 9. Diversity of Life Forms

Which statement represents the best explanation for the observation that the nuclear DNA of wolves and domestic dogs has a very high degree of homology?
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#Question id: 8899

#Unit 9. Diversity of Life Forms

A new species of aquatic chordate is discovered that closely resembles an ancient form. It has the following characteristics: external armor of bony plates, no paired lateral fins, and a suspension-feeding mode of nutrition. In addition to these, it will probably have which of the following characteristics?