Which of the following statements regarding Nucleotide Excision Repair (NER) and Base Excision Repair (BER) is true? 1. Both NER and BER involve the removal of one or more damaged bases by a nuclease. 2. Only NER involves the action of DNA ligase to seal nicks in the DNA backbone. 3. Both NER and BER can be activated by exposure to visible light. 4. Both NER and BER involve the creation of an apyrimidinic (AP) site.