In which part of the government, according to the constitution, is the number of representatives based on population

The house of representatives is correct.  As printed and quoted "The Constitution provides for proportional representation in the U.S. House of Representatives and the seats in the House are apportioned based on state population according to the constitutionally mandated Census. "

eli whitney was an american inventor best known for inventing the cotton gin. this was one of the key inventions of the industrial revolution and shaped the economy of the antebellum south.

you did not put the article. so i cannot answer the question.