Multiple ChoiceSingle-celled prokaryotes had Earth to themselves for approximately __________. 1873views
Multiple ChoiceYou are watching a movie in which one of the characters excitedly claims to have found human remains in Asia dated at 10 million years old. The date was obtained by carbon-14 dating. What is your reaction? 2047views
Multiple ChoiceWhat evidence most strongly suggests that an impact by an asteroid or meteorite may have caused the extinction of the dinosaurs? 2713views
Multiple ChoiceThe early atmosphere on Earth is thought to have lacked which of the following gases? 2091views
Multiple ChoiceMany researchers now believe that the first self-replicating molecules were __________. 2019views
Multiple ChoiceWhat were the two major "problems" that had to be solved before plants, animals, and fungi could fully move into terrestrial habitats? 1539views
Multiple ChoiceIn the species selection model, __________ is to macroevolution as __________ is to microevolution. 1945views
Multiple ChoiceAlthough they originated around 180 million years ago, mammals underwent an adaptive radiation starting approximately 65 million years ago. Why? 2576views
Multiple ChoiceAbiotically produced vesicles display which of the following rudimentary qualities necessary for life? 1624views
Multiple ChoiceWhat evidence supports the hypothesis that mitochondria and plastids evolved from prokaryotic endosymbionts? 2362views
Multiple ChoiceThe Miller and Urey abiotic synthesis experiment (and subsequent, similar experiments) showed that __________. 1839views
Multiple ChoiceWhat prokaryotic adaptation occurred during the oxygen revolution and opened up the possibility for energy-demanding multicellular life-forms? 1699views