The main phenomenon that increases the efficiency of gas exchange in fish gills is the
A. countercurrent exchange mechanism.
B. co-current exchange mechanism.
C. high degree of oxygen saturation of water.
D. back-and-forth movement of water that maximizes oxygen uptake.
E. very high blood pressure found in the circulatory system of fishes.
A. countercurrent exchange mechanism.
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Jerry is six years old. His sister Hanah has the autosomal recessive condition neuronal ceroid lipofuscinosis that affects learning and coordination. Their parents are healthy. Given that Jerry has a normal phenotype and is not affected by the disorder, the probability that Jerry is a homozygote for the wild type allele of the gene that causes the condition is
A) 1/8. B) 1/4. C) 1/3. D) 2/3.
Which of the following correctly indicates the terms in order of increasing size?
a. oxygen, hemoglobin, red blood cell, capillary b. hemoglobin, oxygen, capillary, red blood cell c. red blood cell, oxygen, capillary, hemoglobin d. capillary, red blood cell, hemoglobin, oxygen
A fungi is best described as a ________
a. seed producing autotroph with cell walls of chitin b. seed producing heterotroph with cell walls of cellulose c. spore producing heterotroph with cell walls of chitin d. spore producing autotroph with cell walls of chitin e. spore producing heterotroph with cell walls of cellulose
What kind of analysis focuses on the order in which derived characters appeared in organisms?
a. cladistic analysis b. traditional classification c. taxonomy d. anatomy