A force is when two forces cancel each other out and do not affect the motion of an object

Friction and gravity are at work in each picture. Explain how each are at work and how they work together. Balanced forces - Two or more opposite forces are balanced forces if their effects cancel each other and do not cause a change in an object's motion.

Explanation:

Balanced forces are equal and opposite forces that act on the same object. That's why they cancel out. Action-reaction forces are equal and opposite forces that act on different objects, so they don't cancel out. In fact, they often result in motion.

i think a) betsy can donate only blood to mark is correct because, mark and betsy have the same blood type. whereas nobody else has b+ blood so betsy can't donate to them.

it would lead to upper respiratory infections and pneumonia.