Identify whether the statement is true or false, and why. “each type of receptor protein is specific to a certain signal or type of signal.” a. true b. false, it should read “receptor proteins can receive signals from many types of signal molecules.” c. false, it should read “receptor proteins are only used in synapses to receive neurotransmitters.” d. false, it should read “receptor proteins are universal and can receive signals from any type of signal molecules.”