Why is the runoff from fertilized agricultural fields, even if free of pesticides, often harmful to the ecosystems of temperate lakes?
A) Fertilizer compounds create large hydrothermal vent communities that kill lake organisms.
B) The runoff causes heavy growth of algae, which eventually die and decompose, causing oxygen depletion.
C) Runoff water pools at the lake's bottom, where the fertilizer compounds react with materials in the sediment to form toxic substances.
D) The runoff is acid, and acidification kills key lake organisms.
Answer: B
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Examine Figure 24.2 in your text. Which of the following groups is monophyletic?
A. humans plus chimpanzees and bonobos B. gorillas plus chimpanzees and bonobos C. gibbons plus Old World monkeys D. gibbons plus orangutans E. gibbons plus orangutans plus gorillas
The effect of positive assortative mating is to
A) increase the number of homozygotes in the population. B) increase the number of heterozygotes in the population. C) reduce the number of individuals with diseases in the population. D) increase the fertility of individuals in the population.
A solution has been prepared by mixing glucose in water. Which one of the following statements CORRECTLY describes this solution?
A) Both water and glucose are solutes. B) Both water and glucose are solvents. C) Water is the solute, and glucose is the solvent. D) Water is the solvent, and glucose is the solute.
Microorganisms require large quantities of this nutrient for use in cell structure and metabolism:
A. element B. macronutrient C. water D. growth factor E. trace element