Task: Question Answering
Input (English): Background Paragraph: No doubt you already have a good idea of what temperature is. You might say that it’s how warm or cool something feels. In physics, temperature is defined as the average kinetic energy of the particles of matter. When particles of matter move more quickly, they have more kinetic energy, so their temperature is higher. With a higher temperature, matter feels warmer. When particles move more slowly, they have less kinetic energy on average, so their temperature is lower. With a lower temperature, matter feels cooler. 
Story: Two physicists studied the influence of kinetic energy on the environment. Will studied high temperature environments, while his pal Don studied cooler environments. 
Question: Which person observed more particles of matter moving slower?
Output (English): Don.