Question: A student investigates the effect of temperature on the distance a caterpillar travels in one minute. The student performs the investigation at four different times of day using one caterpillar. This experiment could be improved if the student

  Options: 
 A. uses more than one caterpillar.
 B. performs the investigation on a wet surface.
 C. uses earthworms instead of caterpillars.
 D. performs the investigation at the same time on four days.
Answer: A