O is what should go in the blank. O stands for Oxygen.
Answer: to find a cure for the common cold to produce insulin for diabetics
Explanation: It has helped many people
A spring scale is a type of weighing scale, it works because it uses a spring that is proportional to the distance that the spring is from its resting position.
No, There are not likely to form in areas that experience a lot of erosion on a daily basis.
