What are gaseous planets composed of?

Related questions

• Which planets is least like earth in size and composition?
• In what ways are Terrestrial planets different from Jovian planets?
• Why are planets and satellite round while asteroids irregular?
• Why do Uranus and Neptune appear to be blue?
• How does the earth's moon compare to moons of gas giant planets?
• Why is it important for scientist to determine the temperature ,age and composition of other...
• What are the properties of terrestrial and gaseous planets.?
• Why are outer planets gaseous in nature whereas inner planets in our solar system are rocky?
• How are gaseous planets formed?
• How did gas giant planets form?