Infer weather balanced forces must be acting on a car moving at a constant speedi know this question is really last min but i need it by 5 min

The direction of motion is changing, so the car is accelerating. By Newton's second law, an unbalanced force must be acting on the car if it is accelerating.

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.