Final answer:
The greatest ocean depth is found at the Challenger Deep in the Mariana Trench, at about 11,000 meters deep. This and other ocean zones like the photic, aphotic, and abyssal can be depicted on a vertical number line showing different depths.
Step-by-step explanation:
The greatest ocean depth on Earth is found at the Challenger Deep in the Mariana Trench, which is approximately 11,000 meters (about 36,000 feet or almost 7 miles) deep.
To visualize this on a vertical number line, we would represent the surface of the ocean at 0 meters and mark the Challenger Deep at -11,000 meters. Along this line, we could also indicate various ocean zones.
For instance, the photic zone, where photosynthesis can occur due to sunlight penetration, extends down to about 200 meters. Below this is the aphotic zone, reaching depths of up to 4,000 meters, where light is absent.
The abyssal zone starts at 4,000 meters and goes to the bottom of the ocean, housing organisms that thrive in very cold, high-pressure environments without sunlight. Chemosynthetic bacteria found near hydrothermal vents in this zone form the base of a food chain independent of sunlight.