Answer:
The egg contains both food and mitochondria in addition to its vital DNA, thats why it is much larger. The sperm cell has to be much smaller than the egg cell, because it is the one that swims. If a sperm cell were as big as an egg, it would not be able to move very fast nor very far.
I believe it’s your head since it has more friction
It’s the last one emissions ejected out from smokestacks