To determine which phase of the Moon results in the greatest difference between high tide and low tide, we need to consider the positions of the Earth, Moon, and Sun in relation to each other.
The greatest difference between high tide and low tide, known as "spring tides," occurs when the Earth, Moon, and Sun are aligned (in a straight line). This alignment typically happens during the full moon and new moon phases.
- Full Moon (when the Earth is between the Sun and the Moon): The gravitational pull from both the Moon and the Sun works together, resulting in high tides.
- New Moon (when the Moon is between the Earth and the Sun): Similarly, the gravitational forces are aligned, leading again to the highest high tides and lowest low tides.
In contrast, during the first quarter and third quarter phases (when the Moon is at a right angle to the line connecting the Earth and the Sun), the gravitational forces partially cancel each other out, resulting in lower high tides and higher low tides, which are known as "neap tides."
Without the actual diagram to see the location of each phase labeled W, X, Y, and Z, I would suggest checking which of those labels corresponds to either the full moon or new moon. That would be the answer indicating the phase of the Moon that causes the greatest difference between high tide and low tide.
If you provide the descriptions of each phase, I can help identify the correct answer!