Someone pls help me to understand what the lock and key theory is for how enzymes work. (use diagrams if it helps)

according to this theory both enzymes and substrate possess specific shapes that fit exactly into one another.This model explains specificity.

general example when we open the door of our house we use a specific key to open the door not all keys will open the door of our house.In this example the key is substrate and the door or lock is the enzyme that fits into specific substrate.

lizards have adapted to life in the desert. some desert lizards have toes with spiny scales to them run across the sand without sinking. some use the sand to hide from predators, or to search for small animals that they prey upon.

a. by using fur or clothes to trap heat energy near the body