Leaves on a cactus and wings on flightless birds are examples of which of the following?
a. Vestigial structures
b. Homologous structures
c. Vicariance
d. Mutation
a. Vestigial structures
Leaves on a cactus and wings on flightless birds are examples of vestigial structures.
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During prokaryotic cell division, two chromosomes separate and are distributed to the two ends of the cell by ____
a. the action of the mitotic spindle b. an unknown mechanism c. attachment to actin d. attachment to separating membrane regions e. formation of a newly made cell wall
Experiments called in vitro evolution or directed evolution have shown that:a
RNA can evolve into DNA. b. RNA can evolve to catalyze a variety of reactions. c. RNA can evolve into protein enzymes. d. DNA can evolve the double helix structure. e. RNA can evolve to self replicate.
Which of the following is NOT considered to be well-accepted evidence related to human evolution?
A. Several species of Australopithecus and Paranthropus are known from early hominid fossils. They were herbivores and walked upright. Their fossils are only found in Africa. B. Only a single species of the genus Homo became prominent in Africa and appeared to have made a change from a primarily herbivorous diet to a carnivorous diet. C. Fossils of Homo erectus are found throughout Africa, Europe, and Asia, but not in Australia or the Americas. D. Based on fossil evidence it appears that the climate of Africa was becoming drier during the time that hominid evolution was occurring.
In humans, which genetic mechanism led to the formation of the X and Y chromosomes?
A. Translocation B. Nondisjunction C. Inversion D. Reduced crossing over E. Insertion