From the drop-down list, choose the flaw for the given scientific design.

A student wants to determine how well tulips will bloom at high temperatures. She knows they bloom well at room temperature, so she sets up groups at higher temperatures: 80°F, 90°F, and 100°F.

During cooling, the kinetic energy of the molecules falls. why does this happen? a. the motion of the molecules increases. b. the motion of the molecules slows down. c. the van der waals forces between molecules decrease d. the forces of attraction between the molecules are overcome.