In the countercurrent exchange system of fish gills,
A) blood and water flow in the same direction.
B) blood and water flow in opposite directions.
C) blood and water are separated by a thick polysaccharide barrier.
D) blood flow in the gills reverses direction with every heartbeat.
Answer: B
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Normal blood pressure for an 8-year-old boy is 100/67 mm Hg. The systolic blood pressure is
(a) 33 mm Hg. (b) 100 mm Hg. (c) 67 mm Hg. (d) 167 mm Hg.
In the sweet pea crossing experiment by Bateson and Punnet, the F2 generation had many more offspring with the phenotypes of purple flowers P, long pollen L and red flowers p, round pollen l than expected from independent assortment. This is because
A. In these sweet peas, there are always more PL gametes than there are pl gametes. B. In sweet peas, the alleles for flower color and pollen shape are on the same chromosome. C. There were few recombination events between these genes during meiosis. D. Flower color and pollen shape are within the same linkage group. E. All of these are correct.
A small wooded area was cleared for a new building, but then the builders went bankrupt. Over the ensuing years, plants and animals moved back into the plot in a process called ________
A) climax community B) biological magnification C) secondary succession D) primary succession
Which of these are characteristics of meiosis II?
What will be an ideal response?