In which step of the four-stroke engine cycle does the heat from the combustion reaction cause the pistons to move?

a. combustion and expansion
b. air and fuel intake
c. compression and ignition
d. exhaust

Combustion and Expansion.

Explanation: j took the test!!!

i guess that visual aids present persuasive examples to what you are presenting, some factors would be theme (does it fit with the color, information, what you are presenting), size (can you see it, is it a big enough span of data/information), and overall look of the visual aid.

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weather forecasts are done by collecting data about the current state of the atmosphere mainly the temperature, humidity and wind and using meteorology, to determine the atmosphere that evolves over time. the h and l mean the high and low pressure. the red strip is a warm front. the blue strip is a cold front. the blue and red strip is a stationary front. the purple strip is a occluded front.

explanation: