The main difference between the internal combustion engine and the diesel engine is that the diesel engine

a. has no connecting rods.
b. does not have a crankshaft.
c. has no ignition system.
d. does not utilize pistons.

Gunpowder residue is most likely to show up where on a shooters hands

What are atoms of the same element with varying number of neutrons

The star betelgeuse is about 600 light-years away. if it explodes tonight, a. we'll know because debris from the explosion will rain down on us from space.b. we'll know it immediately because it will be brighter than the full moon in the sky.c. we won't know about it until 600 years from now.d. none of the above.