Question

the ____ of four-cycle diesel engines makes them more powerful and more fuel-efficient than four-cycle gasoline engines.
answer options:
select one of four
high compression
ignition-system function
low pressure
volatility

Explanation:

Diesel engines have a high compression ratio compared to gasoline engines. High compression allows diesel engines to be more powerful and fuel - efficient as it leads to better combustion of fuel. Ignition - system function is different (diesel engines use compression ignition, gasoline use spark ignition) and not the reason for more power and efficiency. Low pressure would not contribute to power and efficiency. Volatility is related to fuel properties, not engine design for power/efficiency here.

Answer:

high compression