Which group of planets is primarily composed of gases and has a thick outer layer?

Which group of planets is primarily composed of gases and has a thick outer layer?

• A. Terrestrial planets
• B. Inner planets
• C. Outer planets
• D. Dwarf planets

Answer: (C)

The group of planets primarily composed of gases and characterized by a thick outer layer is the outer planets. These planets—Jupiter, Saturn, Uranus, and Neptune—are often referred to as gas giants (Jupiter and Saturn) or ice giants (Uranus and Neptune) due to their substantial atmospheres that consist mainly of hydrogen, helium, and other gases. Their thick gaseous layers are a defining feature, differentiating them from terrestrial planets, which are rocky and have solid surfaces. In contrast, terrestrial planets like Earth and Mars are primarily made of rock and metal, and are characterized by solid surfaces and thinner atmospheres. Inner planets, which consist of Mercury, Venus, Earth, and Mars, also fall into the category of terrestrial planets. Dwarf planets, such as Pluto, have their own classification and typically do not fall within the gas giant or terrestrial categories, as they are smaller and often icy bodies. Thus, the categorization of outer planets being primarily gaseous with thick outer layers stands out as the correct choice.

The group of planets primarily composed of gases and characterized by a thick outer layer is the outer planets. These planets—Jupiter, Saturn, Uranus, and Neptune—are often referred to as gas giants (Jupiter and Saturn) or ice giants (Uranus and Neptune) due to their substantial atmospheres that consist mainly of hydrogen, helium, and other gases. Their thick gaseous layers are a defining feature, differentiating them from terrestrial planets, which are rocky and have solid surfaces.

In contrast, terrestrial planets like Earth and Mars are primarily made of rock and metal, and are characterized by solid surfaces and thinner atmospheres. Inner planets, which consist of Mercury, Venus, Earth, and Mars, also fall into the category of terrestrial planets. Dwarf planets, such as Pluto, have their own classification and typically do not fall within the gas giant or terrestrial categories, as they are smaller and often icy bodies. Thus, the categorization of outer planets being primarily gaseous with thick outer layers stands out as the correct choice.