Which of the following describes a reason why companies irradiate some fruits and vegetables before they are sold to the public?
A: to extend the shelf life by killing existing microorganisms

Which of the following is most likely to make a rock crack and crumble?
A: water freezing in a crack in the rock

Which of these is an organism that is unicellular?
A: amoeba

Which of the following is a characteristic of all chemical changes?
A:
A new material is formed.