How do enzymes catalyze chemical reactions?

Enzyme catalyze chemical reaction to speed up the chemical reaction. They lower the activation energy (energy needed to start up a reaction) and thus the chemical reaction speeds up. In the presence of enzymes, the chemical reaction occurs faster. However, if enzymes aren't present in a chemical reaction, it will take more time to complete. So, Enzymes are somehow really important.

well we can't tell you because we cant see the time give a screen shot or something.