The gene that is mutated in cases of cystic fibrosis encodes an ion transporter protein normally expressed in the respiratory and digestive tracts along with other locations. Individuals homozygous for the most common mutation in this gene (ΔF508) died at very early ages prior to the advent of advanced medical intervention. Despite this, the mutation exists at relatively high frequency in populations of European descent. One potential explanation is that heterozygotes for such mutations may be relatively immune to the lethal effects of diseases such as typhoid fever. Which statement below is most accurate?

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#Question id: 12378

#Unit 10. Ecological Principles

Primary succession is occurring.

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#Question id: 5105

#Unit 5. Developmental Biology

Cells transplanted from the neural tube of a frog embryo to the ventral part of another embryo develop into nervous system tissues. This result indicates that the transplanted cells were________.

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#Question id: 19277

#Unit 9. Diversity of Life Forms

which of these statements correctly describes a portion of the pine life cycle? 

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#Question id: 21244

#Unit 7. System Physiology – Animal

Which of the following parts of the eye has the greatest concentration of rods?

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#Question id: 10213

#Unit 6. System Physiology – Plant

What is the reason behind that an organism cannot live or die in the presence of both light and molecular oxygen?