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 moon's orbit is in line with Earth's orbit twice a day.

Earth rotates entirely on its axis once during this time

Earth's revolution is 365 days

The moon revolves around the Earth every 27.3 day

Option (2)

Explanation:

Tides are usually defined as the rise and fall of the sea level due to the gravitational force of attraction between the sun and the earth as well as with the earth and the moon.

The earth rotates around its internal imaginary axis every 24 hours, and during this, the moon revolves around the earth. During this motion, the earth experiences two high tides which are 12 hours apart from one another. It is the time when the moon and the earth are aligned together, due to which there occur bulges in both the sides of the earth. It is due to the gravitational force between the moon and the earth and also because of the centrifugal force generated from the rotation of the earth.

Thus, the correct answer is option (2).