#Question id: 5445
#Unit 8. Inheritance Biology
A plant height in Maize is control by 3 pair of polygene .Two varieties of maize averaging 120 and 60 inches in height, respectively, are crossed. The F1 progeny is quite uniform averaging 90 inches in height. What is percent of F2 progeny that is resemble with either 120 cm or 60 cm height?
#Question id: 13129
#Unit 10. Ecological Principles
Biologists performed an experiment with flies to examine the effects of population size on the maintenance of genetic variation and on egg-to-adult survival. From a large source population, they randomly assigned eggs to three experimental populations of size N, equal to 20, 60, and0100. For later generations, they collected N eggs from each population and moved them into identical vials that co0ntained f2re0sh me4d0ium. Th6e0y coun8te0d the number of adult flies that emerged and used tissue samples from the adults for genetic analyses. Genetic variation was measured by scoring alleles at several polymorphic loci and expressed as the average number of alleles at those loci. The results are summarized in Figure 1 and Figure 2 below.
Based on Figure 1, which of the following best describes the change in genetic variation over time?
#Question id: 19451
#Unit 13. Methods in Biology
#Question id: 19454
#Unit 13. Methods in Biology
#Question id: 5678
#Unit 5. Developmental Biology
Following process and their mechanism during fertilization in mammals.
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a. Rheotaxis |
i.A sensing mechanism in which, the oocyte and its accompanying cumulus cells secrete molecules that attract capacitated sperm toward the egg during the last stages of sperm migration |
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b. Chemotaxis |
ii.It is a transient event, and sperm are given a relatively brief window of competence during which they can successfully fertilize the egg. |
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c. Capacitation |
iii.it is the ability to sense temperature difference and preferentially swim from cooler to warmer sites is found only in capacitated sperm. |
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d. Thermotaxis |
iv.Sperm receive long-distance directional cues from the flow of liquid from the oviduct to the uterus and they will migrate against the direction of the flow—using CatSper calcium channels to sense calcium influx and monitor the direction of the current |
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Which of the following option is correct?