How do paragraphs 19-20 contribute to the development of ideas in the text? question 4 options: a they emphasize how little is truly known about how much energy people use and what they use it for. b they stress how complicated it is to get people who use a lot of energy to switch to energy-efficient products. c they show how understanding people and their energy-usage will lead to better energy-saving methods. d they support the claim that watching television is the biggest waste of energy in most households.