Make a sketch showing how nondisjunction in meiosis can result in Down syndrome. What will be an ideal response?
The sketch should show how a gamete can end up with an extra chromosome 21 and should resemble
Figure 16-3 (shown for male gametes) or a corresponding version for female gametes.
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The three groups in the primate lineage are
A. gorillas, bonobos, and chimpanzees. B. prosimians, monkeys, and hominoids. C. monkeys, gibbons, and orangutans. D. hominines, hominids, and hominoids. E. chimpanzees, gorillas, and humans.
Mendel’s principle of independent assortment is explained by which metaphase I event?
a. separation of homologous chromosomes b. crossing-over c. synapsis d. cytokinesis e. random orientation of homologous chromosomes on the metaphase plate
In the accompanying figure, the palisade mesophyll is labeled with the number
:
a. 1
b. 2
c. 3
d. 6
e. 9
In an average ecosystem, about how much energy is present in the organisms at a given trophic level compared to the organisms at the next higher trophic level?
A) a tenth as much B) half as much C) twice as much D) ten times as much