He looked under the microscope at the bacteria surrounding the blue-green mold and noticed that many were dead or dying due to the mold preventing the bacteria from making new cell walls and reproducing.
He looked under the microscope at the bacteria. He was surrounding the blue-green mold. Many were dead or dying due to the mold. This mold was preventing the bacteria from. This mold was making new cell walls. This mold was reproducing. He noticed this.