Which molecules are particles could move through a lipid bilayer without the help of some type of transport protein
1) Small molecules
2) Big molecules
3) Polar molecules
4) non-polar molecules
5) Ions
6) sugar

Which of the following types of pollution is most responsible for large numbers of deaths worldwide because of unsafe drinking water? (a) nutrient pollution (b) thermal pollution (c) pathogen pollution (d) sediment pollution