How is a front defined in terms of weather ? . a) the leading edge of an anticyclone flow. b) the trailing edge of a warm front. c) the physical boundary between two or more air gasses. d) the stationary boundary between a warm and cold air mass

C) The physical boundary between two or more air gasses.

Explanation:

A weather front is a transitional zone between the two air masses. It forms a physical boundary between the two air masses that exhibit differences in the temperature, humidity and densities. It is responsible for bringing the change in the climatic condition of the region. The types of weather fronts are cold, warm, occluded and stationary.

for this one it would be d bump/forearm pass

explanation:

a fuel engine ( known as a gasoline engine in american english )is an internal combustion engine with spark ignition, designed to run on petrol (gasoline) and similar volatile fuels.