What characteristic is shared between all of the outer planets?
A.
They have no moons that orbit them.
B.
They are made mostly of gaseous materials.
C.
They are all very warm, similar to Venus.
D.
They orbit the Sun opposite to Earth.
B.
They are made mostly of gaseous materials.
B. They are made mostly of gaseous materials.
The correct answer is B. The characteristic shared between all of the outer planets is that they are made mostly of gaseous materials.
To arrive at this answer, we can recall some basic knowledge about the outer planets, also known as the gas giants. The outer planets in our solar system are Jupiter, Saturn, Uranus, and Neptune. Unlike the inner planets (Mercury, Venus, Earth, and Mars), the outer planets are located further from the Sun and are composed mostly of hydrogen and helium gases, along with other volatile compounds.
Option A, stating that the outer planets have no moons orbiting them, is incorrect. All four outer planets have multiple moons that orbit around them. Jupiter, for example, has at least 79 known moons.
Option C, suggesting that the outer planets are very warm similar to Venus, is also incorrect. Venus is an inner planet and has a thick atmosphere that results in a runaway greenhouse effect, making it the hottest planet in our solar system. The outer planets, on the other hand, do not have such extreme temperatures.
Option D, saying that the outer planets orbit the Sun opposite to Earth, is also incorrect. While it is true that the orbits of the outer planets are farther from the Sun compared to Earth's orbit, their direction of orbit is the same as Earth's, which is counterclockwise when viewed from above the Earth's North Pole.
Therefore, the correct answer, B, is that the outer planets are made mostly of gaseous materials.