Final answer:
Average speed is calculated by the total distance traveled divided by the elapsed time and accounts for variations in speed, while instantaneous speed is the speed at a specific moment in time.
Step-by-step explanation:
The difference between average speed and instantaneous speed lies in how each is measured over time. Average speed is calculated by taking the total distance traveled and dividing it by the elapsed time, whereas instantaneous speed is the speed of an object at a specific moment in time and has no direction associated with it.
Considering the options provided in the question, the correct answer for what makes something an average speed instead of instantaneous speed is: d. It accounts for variations in speed over time.
To give an example, if an athlete runs a sprint from the starting line to the finish line, measuring the total time taken and the distance covered will allow us to calculate the average speed. On the contrary, instantaneous speed might be represented by the speed on a speedometer at any given moment during the sprint, which does not take into account the total distance or time.
Therefore answer is c. It represents the total distance traveled.