Please help me with this science problem! willing to give 50 POINTS!!!

Iagree c would be the answer

Examples: mental health problems cardiovascular disease obesity and other eating disordersmenstrual problems skin and hair problems

Answertraveling around a circular trackexplanation"traveling around a circular track" is the best answer as you could be traveling around a circular track at a constant speed. your velocity would therefore have the same magnitude but will always be constantly direction. since acceleration is the rate of change of velocity, the rate of change will only involve the direction of velocity and not the magnitude.wrong choices: "an object at rest" does not accelerate at all"increasing speed while traveling around a curve" means that the acceleration will not be constant due to only change in direction; it will be constant due to both magnitude and direction"an object in free fall" does not necessarily change direction 

Amicroscope, because these cells are so small that you would not be able to see them, or what they attack without it.