Transplantation of different regions of the presomitic mesoderm (PSM) to the limb field causes changes in limb size. Following statements are:

A. Transplanting PSM from the level of the presumptive forelimb to the flank (region between the forelimb and hindlimb) results in a larger forelimb bud.

B. Transplantation of PSM from the flank region to the level of the presumptive forelimb results in a smaller forelimb bud.

C. Transplanting PSM from the level of the presumptive forelimb to the flank (region between the forelimb and hindlimb) results in a smaller forelimb bud.

D. Transplantation of PSM from the flank region to the level of the presumptive forelimb results in a larger forelimb bud.

Which of the following combination are correct?

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#Question id: 23678

#Unit 13. Methods in Biology

Which component is not necessary for a PCR experiment?

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#Question id: 3819

#Unit 3. Fundamental Processes

DNA replication is studied in a newly discovered bacterium. It takes 30 min for the bacterium to complete a round of replication at 37oC. A Meselson-Stahl-type experiment was performed. The bacteria were grown for several generations in 14N-medium and then switched to 15N-medium. The DNA molecules were then analyzed.

After one generation in 15N-medium, the DNA is denatured and analyzed in a CsCl gradient. If the single-stranded DNA forms two bands, one with heavy density and one with light density, what conclusion could be drawn about the mechanism of DNA replication in this bacterium?

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#Question id: 12474

#Unit 10. Ecological Principles

The most common kind of dispersion in nature is

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#Question id: 7051

#Unit 5. Developmental Biology

Which of the following is not maternal dorsalizing factors in amphibia?

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#Question id: 4392

#Unit 3. Fundamental Processes

X chromosome inactivation in mammals is mediated by