Answer
The answer is Both
Step-by-step explanation
The lower-end operation of an engine can be achieved through;
• A power load that occurs from the expansion of burning gases in the combustion chamber that will further push down the piston and turn the crankshaft.
• A lower-end engine operation can also occur when the connecting rod is pulling the piston down from the top dead center, the weight of the piston plus caused by ring friction and skirt drag.