The 4 x 100 meters relay is a running race where teams of four people take turns running 100 meters each. The 100 meter is a short distance race where runners have to run really fast to reach the finish line.
So, in this relay race, there are four runners in each team, and each runner has to run 100 meters as fast as they can. But they cannot start running until the previous runner has passed a baton, which is a special stick-like object, to them.
Think of it like a game of hot potato - the baton is passed around the team in a specific zone and the runners cannot go outside that area until the baton has been passed to them.
The aim of the race is for each team to cross the finish line first, but to do that, they need to have really fast runners who can keep a good pace and pass the baton quickly and smoothly.
It's a really exciting race to watch because there are lots of different elements involved, and each team has to work together to make sure they don't make any mistakes.