Why are packed juices contaminated with yeast

Alaska and northern canada have a diet rich in vitamin d and their skin color is darker than predicted on the basis of iv intensity at their latitude. explain the observation:

How is the motion of the particles of water at 80 ⁰c different from the motion of the particles of water when it is 30 ⁰c?

Which image shows labeled organelles that are present only in plant cells?