(at around 11 mins) When Mulder, Scully, and the sheriff are speaking outside the apartment building, the cut from the wide shot to the single of Mulder reveals the same wall in the background, but with different physical locations for the actors. In the wide, Mulder plants himself with the wall (reading "Manager's Office") directly to his right. In his close-up, the same wall is now behind him. This is either a blocking error for Duchovny or a very narrow area the camera could focus and the error is thus revealed through editing.
Scully finds the chemical contains the same DNA they found in episode #1.23, "The Erlenmeyer Flask", in the bovine hormone and says that it has unidentified amino acids. DNA does not contain amino acids; it contains nucleic acids.