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D) They were delivered in the form of polypeptides.4) Which of the following is the correct sequence of events in the origin of life? B) earlier genetic systems than those based on DNA. D) the delivery of organic matter to Earth by meteors and comets.
uncertainty about which gases comprised early Earth's atmosphere A) 1 only B) 2 only C) 1 and 2 D) 1 and 3 E) 2 and 32) How were conditions on the early Earth of more than 3 billion years ago different from those on today's Earth?
A) Only early Earth was intensely bombarded by large space debris. C) Less ultraviolet radiation penetrated early Earth's atmosphere.
C) easy to determine, as long as there is enough metamorphic rock nearby. E) massive eruptions of deep-sea vents.21) Which of these observations gives the most support to the endosymbiotic theory for the origin of eukaryotic cells? E) existence of prokaryotes around hydrothermal vents on the ocean floor.24) Which of the following characteristics should have been possessed by the first animals to colonize land? were probably herbivores (ate photosynthesizers) 2. B) The organism must have multiple paired appendages along the length of its body. D) silencing (loss of expression).32) Larval flies (maggots) express the Ubx gene in all of their segments, and thereby lack appendages. D) Two of the responses above are correct.33) How many of the following statements concerning the loss of hind limbs during whale evolution are true? It is well documented by a series of transitional fossils. It explains why modern whales have vestigial pelvic girdles. It involved changes in the sequence or expression of Hox genes. E) evolution generally progresses toward some predetermined goal.40) Fossil evidence indicates that several kinds of flightless dinosaurs possessed feathers.
D) difficult to determine the absolute age of the fossil, because the "marker fossils" common to igneous rock will be absent. A) the existence of structural and molecular differences between the plasma membranes of prokaryotes and the internal membranes of mitochondria and chloroplasts B) the similarity in size between the cytosolic ribosomes of prokaryotes and the ribosomes within mitochondria and chloroplasts C) the size disparity between most prokaryotic cells and most eukaryotic cells D) the observation that some eukaryotic cells lack mitochondria22) Which event is nearest in time to the end of the period known as snowball Earth? C) The organism has the genetic potential to have a relatively complex anatomy. E) changes in homeotic genes.31) The loss of ventral spines by modern freshwater sticklebacks is due to natural selection operating on the phenotypic effects of Pitx1 gene A) duplication (gain in number). If this same gene continued to be expressed throughout subsequent developmental stages, except in the head region, and if the result was a fit, sexually mature organism that still strongly resembled a maggot, this would be an example of A) paedomorphosis. If some of these feather-bearing dinosaurs incubated clutches of eggs in carefully constructed nests, this might be evidence supporting the claim that A) dinosaurs were as fully endothermal (warm-blooded) as modern birds and mammals.
9) If natural selection in a particular environment favored genetic systems that permitted the production of daughter "cells" that were genetically dissimilar from the mother "cells," then one should expect selection for which of the following? polynucleotide polymerase with low mismatch error rates II.