Select all the statements that are true regarding enzymes. they allow reactions to proceed faster. they are biological catalysts. their reactions are referred to as catalyzed reactions. they increase the energy of activation.

Technically, enzymes are specialized proteins that help cells do some chemical reactions. Most chemical reactions don't start spontaneously, even if they are energetically favored. For example, take a paper that burns (combustion). This reaction gives off energy but one does not see paper combusting without outside intervention; one needs to put in some energy for the reaction to start. This energy is called activation energy. The role of the enzymes is to reduce the activation energy of a specific reaction (or at most some reactions). Thus, reactions that would not take place without an enzyme or would be very slow, are accelerated a lot since the activation barrier goes down. Hence, the correct statements are that enzymes speed up reactions, enzymes are biological catalysts (anything that speeds up a reaction is a catalyst to that reaction; enzymes are also biological in nature), their reactions are referred to as catalyzed (since there is a catalyst present).
The last sentence is false since enzymes decrease the energy of activation for the reaction they are catalyzing (if they increased it, this would make the reaction harder and slower).