Final answer:
There are two high tides and two low tides every 24 hours due to the Moon's gravity.
Step-by-step explanation:
In the context of the Earth-Moon system, there are two high tides and two low tides every 24 hours.
The Moon's gravity causes these tides by attracting the water on the near side of Earth more than the water on the far side. As a result, a high tide is created on the side of Earth nearest to the Moon, where the Moon's gravitational pull is strongest. Similarly, there is a high tide on the opposite side of Earth, as Earth is pulled toward the Moon more than the water on the far side.
As Earth rotates, the tidal bulge (an effect of the tidal forces between the Moon and Earth) keeps its orientation with the Moon. Thus, there are two tides per day, occurring approximately every 12 hours and 25.2 minutes. These tides are known as the semi-diurnal tides.