In a thymectomized animal, which of the following is irradiated and reconstituted with bone marrow cells?

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#Question id: 10652

#Unit 10. Ecological Principles

Which factors (limited space or overcrowding; limited food; Predators; parasite and diseased) tend to act in a density-dependent manner; Tony Sinclair (1989) many studies of density dependence in 51 populations of insects, 82 populations of large mammals, and 36 populations of small mammals and birds. Which of the following observation is most likely true?

a) Insects showed a wide variety of causes of density dependence and no one density-dependent factor was of overriding importance

b) The lesser the amount of available food, the greater the mortality of large mammals

c) Space and social interactions were more important for smaller mammals and birds, because they are more territorial

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#Question id: 15153

#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 parallel with recessive 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.

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#Question id: 15298

#Unit 5. Developmental Biology

In mammalian development Prior to blastocyst formation, each embryonic blastomere expresses ________ transcription factors and appears to be capable of becoming either ICM or trophoblast.

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#Question id: 28475

#Unit 5. Developmental Biology

which factors involved in Feedforward circuit?

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#Question id: 19746

#Unit 3. Fundamental Processes

Cells that lack POT1 protein show dramatically