Simplify the following text for a Grade 9 native English-speaking person.
Original: Of the thirty-nine elements of section 51 , a few have become critical in determining the scope of Commonwealth government action , including the Trade and Commerce Power , the Corporations Power and the External Affairs Power .
Simplified: Of the thirty-nine parts of section 51 , a few have become very important in deciding how much power the Commonwealth government has in law . These include the Trade and Commerce Power , the Corporations Power and the External Affairs Power .