50% of the planets are made mainly of gas true or false

Answer: I think the answer is true

Explanation: If you think about it, the terrestial planets (being venus, earth, mars, and mercury) are made up very little gas which are carbon dioxide, nitrogen and oxygen, and the gas giants (being jupiter, saturn, neptune, and uranus) have gases such as hydrogen and helium. Thus meaning, the terrestial planets could be a part of it and the gas giants are the most. So yes, the answer is true.