Suppose that the number of bird species is determined mainly by the number of vertical strata found in the environment. If so, in which of the following biomes would you find the greatest number of bird species?

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#Question id: 12379

#Unit 7. System Physiology – Animal

A healthy 29-year-old man runs a 10-km race on a hot day and becomes very dehydrated. Assuming that his antidiuretic hormone levels are very high, in which part of the renal tubule is the most water reabsorbed?

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#Question id: 10370

#Unit 6. System Physiology – Plant

Rhizobial genes that participate in nodule formation are called nodulation (nod) genes. Only one of the nod genes, the regulatory and constitutively expressed and regulates the transcription of the other nod genes;

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#Question id: 1564

#Unit 4. Cell Communication and Cell Signaling

When antibodies bind antigens, the clumping of antigens results from ________.

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#Question id: 3615

#Unit 8. Inheritance Biology

What are alleles?

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#Question id: 15152

#Unit 8. Inheritance Biology

In this problem we will explore some of the many ways that mutations in two different genes can interact to produce different Mendelian ratios. Consider a hypothetical insect species that has red eyes. Imagine mutations in two different unlinked genes that can, in certain combinations, block the formation of red eye pigment yielding mutants with white eyes. In principle, there are two different possible arrangements for two biochemical steps responsible for the formation of red eye pigment. The two genes might act in series such that a mutation in either gene would block the formation of red pigment. Alternatively, the two genes could act in parallel such that mutations in both genes would be required to block the formation of red pigment.

Further complexity arises from the possibility that mutations in either gene that lead to a block in enzymatic activity could be either dominant or recessive. If the crosses is made between a wild type insect with red eyes and a true breeding white eyed strain with mutations in both genes. Such considerations yield the Pathways in series with dominant mutations in both genes, determine the phenotype of the F1 progeny and the expected phenotypic ratio of red to white eyed insects in the F2.