How did humans colonize the New World?
A. Christopher Columbus and a host of other explorers were the first to colonize the Americas.
B. Humans drifted across the Atlantic on primitive canoes.
C. Early humans walked across a land bridge during periods of lowered sea level.
D. Humans were present during the break-up of Gondwana.
Answer: C
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In which of the following is auxin involved?
a. embryonic development b. formation of plant parts c. formation of lateral roots d. differentiation of vascular tissues e. auxin is involved in all of these
With metal pollutants, the best phytoremediation uses ____
a. hydrologic injections that dilute the groundwater b. chemical injections that degrade the pollutants c. plants that take up toxins and store them in aboveground tissues d. plants that prevent the toxins from being absorbed in their tissues e. plants that can breakdown the toxins and release them into the air
Which one of the following correctly describes the order of stem cells from the lowest degree of flexibility to the highest degree of flexibility?
A) unipotent< multipotent < pluripotent < totipotent B) multipotent< unipotent < pluripotent < totipotent C) pluripotent< unipotent < totipotent < multipotent D) unipotent< multipotent < totipotent < pluripotent
Which of the following best describes how chromosomes move toward the poles of the spindle during mitosis?
A) The chromosomes are "reeled in" by the contraction of spindle microtubules. B) Motor proteins of the kinetochores move the chromosomes along the spindle microtubules. C) Nonkinetochore spindle fibers serve to push chromosomes in the direction of the poles. D) The chromosomes are "reeled in" by the contraction of spindle microtubules, and motor proteins of the kinetochores move the chromosomes along the spindle microtubules. E) The chromosomes are "reeled in" by the contraction of spindle microtubules, motor proteins of the kinetochores move the chromosomes along the spindle microtubules, and nonkinetochore spindle fibers serve to push chromosomes in the direction of the poles