Why is it beneficial to use low viscosity engine oil?

Low viscosity engine oil flows more easily between engine parts, which helps generate less friction. Less friction means the engine runs more efficiently, leading to reduced fuel consumption. This is why options 1 and 2 are correct. Option 3 is incorrect because engine oil, regardless of viscosity, is hazardous waste and must be disposed of properly, not as household waste. Understanding this helps you choose oils that improve engine performance and follow environmental regulations.