#Question id: 1649
#Unit 4. Cell Communication and Cell Signaling
Which of the following gene clusters do NOT contribute to antigen binding?
#Question id: 18912
#Unit 13. Methods in Biology
#Question id: 4972
#Unit 11. Evolution and Behavior
Fossils of Lystrosaurus, a dicynodont therapsid, are most common in parts of modern-day South America, South Africa, Madagascar, India, South Australia, and Antarctica. It apparently lived in arid regions, and was mostly herbivorous. It originated during the mid-Permian period, survived the Permian extinction, and dwindled by the late Triassic, though there is evidence of a relict population in Australia during the Cretaceous. The dicynodonts had two large tusks, extending down from their upper jaws; the tusks were not used for food gathering, and in some species were limited to males. Food was gathered using an otherwise toothless beak. Judging from the fossil record, these pig-sized organisms were the most common mammal-like reptiles of the Permian. Anatomically, what was true of Lystrosaurus?
#Question id: 267
#Unit 1. Molecules and their Interaction Relevant to Biology
#Question id: 3506
#Unit 11. Evolution and Behavior
An altruist provides help worth 9 units of fitness to a recipient, at a personal cost of 2 unit of fitness. As per kin-selection theory, the minimum value of genetic relatedness between the actors and the recipients that is necessary to maintain altruism in the population is