What is upper body vs lower body connection in BJJ?

To grapple, you need to be connected to your opponent - either to their upper body or lower body or both. For takedowns, connecting to the lower body means grabbing one leg (single leg) or two legs (double leg). Connecting to the upper body uses underhooks, body locks, overhooks, or jacket grips. For guard, lasso and spider are upper body guards while de la Riva and reverse de la Riva are lower body guards.