**Question 13:** Human Activity and San Marcos Salamanders Survival **Question 14:** Bactericide Impact on Nitrogen Cycle **Question 16:** Wildfire Effect on Carbon Dioxide Removal

Question: 13. The San Marcos salamander, Eurycea nana, is a light reddish-brown translucent salamander about 2-5 cm in length. E. nana is found only in Spring Lake and a portion of the San Marcos River. Which human activity would most likely decrease the ability of the salamanders to survive? A.Tourism that helps fund the educational programs related to river ecosystem conservation B.The addition of a new food source into the river that limits competition for resources C.Increasing water consumption that decreases the flow of clean water from the springs that feed the river D.Public transportation that reduces the number of automobiles that contribute to pollution runoff into the river 14. Nitrogen is an essential component of all living things. However, atmospheric nitrogen is unavailable for organisms to use. Through various processes and chemical changes, nitrogen moves through the biosphere, atmosphere, and geosphere in different forms, making it available for all organisms. Atmospheric nitrogen is deposited in the soil and surface waters primarily through precipitation. Once in the soil, microorganisms break down the nitrogen into different forms, which is then taken up by plants. Nitrogen eventually makes its way back into the atmosphere. What would happen within the nitrogen cycle if a bactericide, a substance that kills bacteria, was added to the soil? A.Nitrogen would be blocked from entering the soil, making it unavailable for plants to use. B.The rate at which nitrogen is broken down would increase, resulting in faster absorption by plants. C.More nutrients would be added to the soil, increasing the amount of nitrogen available to the plants. D.Microorganisms would not be present to break down the nitrogen into a usable form for plants. 16. What would be the most likely effect of a wildfire that burned a large area of a forest? A.The availability of fossil fuels for use by industries in the area would be reduced. B.More sugars and starches would be available for animals in the area. C.An increase in animal respiration would increase the release of carbon dioxide in the area. D.Less carbon dioxide would be removed from the atmosphere in the area by plants.