<span>Enzymes are catalysts in chemical reactions. What this means is that they speed up chemical reactions, which in turn means that all the actions necessary for our metabolisms occur as a result of catalysts. This goes from fighting illnesses and diseases to dissolving food. We couldn't live without them because our metabolisms would be so slow that we would die as nothing could work.</span>
B E D hehsbshajshajsbsbhs sorry if its wrong but i rember doing this lol
Answer:
True. The heart contracts twice per heartbeat. One contraction is the ventricular and the other one is the artrial.
