Red-green color blindness is an X-linked recessive
trait in humans. A color-blind woman and a man
with normal vision have a son. What is the
probability that the son is color blind?
a. 100%
b. 75%
c. 50%
d. 25%
e. 0%
Answer: a
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The discovery of identical plant and animal fossils by Alfred Wegener in 1915 on either side of the Atlantic Ocean is
evidence of ____.
a. analogous structures b. catastrophism c. plate tectonics
d. comparative morphology e. the great chain of being
The characteristic that enables efficient gas exchange in capillaries is:
a. the very short total length of the capillaries. b. their proximity to the heart. c. thick walls of connective and muscle tissue. d. walls that are only one cell thick. e. vasoconstriction.
Endosymbiosis is an evolutionary theory that explains the origin of eukaryotes and suggests a specific order in which this might have occurred. Ancestral cells engulfed and then began to use the metabolic processes of the smaller cells
Based on shared core processes and features, which statement most accurately describes the order, the theory and the evolutionary implications for all organisms within domain Eukarya? A) Ancestral heterotrophic eukaryotes most likely engulfed both a heterotrophic and an autotrophic prokaryote, whereas ancestral photosynthetic eukaryotes probably provided the host cell for the first mitochondria. Over time, natural selection favored these relationships and these cells became ancestors of all eukaryotes. B) All ancestral eukaryotes would have most likely consumed a nucleus-like prokaryote that eventually became the eukaryotic nucleus. These new eukaryotic cells would have had an advantage over prokaryotic cells by acquiring a nuclear command center for regulating cellular activities. C) As carbon dioxide levels were increasing over time, natural selection would have favored organisms that acquired a photosynthetic prokaryote to convert carbon dioxide into sugars. These would have likely been the first eukaryotic cells. At which point, these ancestral cells engulfed mitochondria-like prokaryotes that would have provided an even greater advantage for cells in this environment. D) As Earth was becoming more aerobic, mitochondria would have provided an advantage to host cells by converting "toxic" oxygen into energy for heterotrophic cells. Since mitochondria are found in all eukaryotes, these combinations likely evolved first. Photosynthetic eukaryotes probably acquired an autotrophic prokaryote, which developed an advantageous symbiotic relationship with the host cell.
The Barr body is the X chromosome in the cell that is expressed, whereas the other X chromosome is inactivated
Indicate whether the statement is true or false