Which of the following best describes a properly controlled experiment

Acar traveld with an average speed of 60 miles per hour for 2 hours. how far did it travel

Common symptoms of an iron-defiency anemia include muscle weakness shortness of breath and lightheadedness why does iron deficiency causes these symptoms

In the respiration-photosynthesis cycle shown above, what are the products of cellular respiration that belong in box 2?