Question

why are there two high tides a day about 12 hours apart from each other?
earth revolves around the sun once during that time.
earth rotates entirely on its axis once during that time.
the moon revolves around earth once during that time.
the moons orbit is in line with earths orbit twice a day.

Explanation:

Tides are caused by the gravitational pull of the Moon (and to a lesser extent, the Sun) on Earth's oceans. As the Earth rotates on its axis approximately every 24 hours, different parts of the Earth pass through the areas of high - tide caused by the Moon's gravitational pull. Since the Moon is also in motion around the Earth, the time between high tides is approximately 12 hours and 25 minutes.

• Option 1: Earth's revolution around the Sun (takes about a year) is not related to the 12 - hour tide cycle.
• Option 2: Earth's rotation on its axis (about 24 hours) is a factor, but it's the combination with the Moon's position that gives the 12 - hour tide cycle. Just Earth's rotation alone (24 hours) would imply a 12 - hour cycle only if there was no Moon movement, which is not the case.
• Option 3: The Moon's revolution around Earth (about 27.3 days) is not completed in 12 hours.
• Option 4: The Moon's orbit is not in line with Earth's orbit (around the Sun) twice a day in the way described. The key is the Moon's gravitational pull and Earth's rotation.

If we assume a correction in the options (for example, if an option was about the combination of Earth's rotation and the Moon's gravitational pull), that would be the correct reasoning. But among the given options, none accurately explain the 12 - hour tide cycle.

Answer:

No correct option provided.