*Question*
Answer the following question given this paragraph: One major factor that limits the length of food chains is energy. Energy is lost as heat between each trophic level due to the second law of thermodynamics. Thus, after a limited number of trophic energy transfers, the amount of energy remaining in the food chain may not be great enough to support viable populations at yet a higher trophic level. The loss of energy between trophic levels is illustrated by the pioneering studies of Howard T. Odum in the Silver Springs, Florida, ecosystem in the 1940s (Figure 46.5). The primary producers generated 20,819 kcal/m2/yr (kilocalories per square meter per year), the primary consumers generated 3368 kcal/m2/yr, the secondary consumers generated 383 kcal/m2/yr, and the tertiary consumers only generated 21 kcal/m2/yr. Thus, there is little energy remaining for another level of consumers in this ecosystem. Q: Energy is lost as heat between each trophic level due to the second law of what? Choices: - reactions - particles - chemistry - thermodynamics A:
**Answer**
thermodynamics

*Question*
Answer the following question given this paragraph: Uranus is so far away that there has been relatively little exploration of the planet. The closest approach was a flyby by Voyager 2 in 1986. Great images have also been taken by the Hubble Space Telescope. Q: What is the name of the spacecraft that has performed the closest flyby of uranus? Choices: - Mercury 7 - centaur 2 - Zodiac 4 - voyager 2 A:
**Answer**
voyager 2

*Question*
Answer the following question given this paragraph: Summary The concentration of a species in solution can be determined by quantitative analysis. One such method is a titration, in which a measured volume of a solution of one substance, the titrant, is added to a solution of another substance to determine its concentration. The equivalence point in a titration is the point at which exactly enough reactant has been added for the reaction to go to completion. A standard solution, a solution whose concentration is known precisely, is used to determine the concentration of the titrant. Many titrations, especially those that involve acidbase reactions, rely on an indicator. The point at which a color change is observed is the endpoint, which is close to the equivalence point if the indicator is chosen properly. Q: What helps determine the concentration of a species in a solution? Choices: - technical analysis - qualitative analysis - fundamental analysis - quantitative analysis A:
**Answer**
quantitative analysis

*Question*
Answer the following question given this paragraph: Wetlands Wetlands are environments in which the soil is either permanently or periodically saturated with water. Wetlands are different from lakes and ponds because wetlands exhibit a near continuous cover of emergent vegetation. Emergent vegetation consists of wetland plants that are rooted in the soil but have portions of leaves, stems, and flowers extending above the water's surface. There are several types of wetlands including marshes, swamps, bogs, mudflats, and salt marshes (Figure 20.33). Q: Wetlands are environments in which the soil is either permanently or periodically saturated with what? Choices: - hydrogen - oil - spores - water A:
**Answer**
water