Explanation: In astronomy, a natural satellite is a celestial body that orbits a planet or smaller body. The Earth has one natural satellite, the Moon. The Moon is a rocky, terrestrial body that orbits the Earth at an average distance of about 384,400 kilometers. It is the fifth-largest natural satellite in the Solar System and the largest relative to the size of its planet, with a diameter about one-quarter that of Earth.
The Moon plays a significant role in Earth's environment. It influences the Earth's tides, which are the rise and fall of sea levels caused primarily by the gravitational interaction between the Earth and the Moon. The Moon also stabilizes the Earth's axial tilt, which helps to maintain a relatively stable climate over long periods.
The Moon is the only natural satellite of Earth, and this fact is a fundamental part of Earth's astronomical characteristics. Other planets in the Solar System have different numbers of natural satellites. For example, Mars has two small moons, Phobos and Deimos, while Jupiter has 79 known moons, and Saturn has 82 known moons. However, Earth's unique feature is that it has only one natural satellite.
Understanding the concept of natural satellites is crucial for comprehending the dynamics of the Solar System and the specific characteristics of Earth. The Moon's presence and its influence on Earth are key elements in the study of astronomy and Earth sciences. Therefore, the correct answer is that the Earth has one natural satellite, the Moon.