The valve seat performs two functions: it provides a seal for the valve in the combustion chamber, and it provides a cool surface to carry heat away from the valve. most valves use a seating angle. a. 30 b. 60 c. 45 d. 15

Based on the graph, how is coal consumption likely to affect future generations? a. the higher our current rate of consumption, the less coal will be available in the future. b. current rates of consumption are irrelevant because new coal will form in the future. c. the lower our current rate of consumption, the more slowly coal will be replenished for the future. d. regardless of current rates of consumption, coal will always be available.