During the stage of internal combustion engine operation in which the piston rises and compresses the fuel in the combustion chamber,
a. both the intake and exhaust valves are closed.
b. both the intake and exhaust valves are open.
c. the exhaust valve is open and the intake valve is closed.
d. the intake valve is open and the exhaust valve is closed.

Complete the sentence to describe the law of conservation of energy. the law of conservation of energy states that energy cannot be created or , but it can be

Which describes increasing the efficiency of energy resource

Scientist have use computer models to create a series of maps that show how susceptible coastal cities in island countries are to the sea rising at different levels.the map shows that a 1 meter rise would swap cities all along the us eastern seaboard. a 6-meter sea level rise with sub merge a large part of florida. thermal expansion has already raise the oceans 10 to 20 centimeters the most likely cause,directly and indirectly, for such a rise in sea level is