A science class investigated the percentage of corn kernels that pop in bags of different brands of popcorn. Fifteen students tested three brands of popcorn each and reported their results to the class. Why did the teacher most likely have so many students report the results? OPTIONS:
- for more accurate results
- for more student participation
- to help simplify the procedure
- to help explain the hypothesis
A: for more accurate results

What is the main source of raw material for the production of plastics? OPTIONS:
- clay
- plants
- petroleum
- sand
A: petroleum

Which of the following best describes the purpose of cellular respiration? OPTIONS:
- to provide energy for cell activities
- to produce sugar for storage in cells
- to release oxygen for breathing
- to supply carbon dioxide for photosynthesis
A: to provide energy for cell activities

In gym class a student kicks a soccer ball high into the air. As the ball goes upward, which type of energy is increasing? OPTIONS:
- kinetic energy
- thermal energy
- potential energy
- mechanical energy
A:
potential energy