42. Which of the following describes a deep zone?
O area just below the epipelagic zone where, even in the most optimal conditions, sunlight fades out and is extinguished at 3,000 feet
O one of the four vertical sections of the intertidal zone regularly covered with water
O at the depths of 13,000 to 20,000 feet, a zone resembling a bottomless pit of complete darkness
O the area of highest elevation in ocean tidal zones
