Will give brainiest for the best detailed answer. Thanks a lot :)

WHAT HAPPENS TO OUR BODIES WHEN WE EXERCISE?
What is happening to her circulatory system?
When you exercise, or play football in this case, you are working your muscles and certain places in the body. When this happens, your muscles respire (burn the FOOD to produce ENERGY) more faster than they would normally, so the demand for OXYGEN and GLUCOSE is increased.
As the muscles are performing cellular RESPIRATION quicker than the norm, they need oxygen and glucose to reach them faster (glucose and oxygen are the components for cellular respiration), and also they need to get rid of their CO2 (products of cellular respiration are CARBON DIOXIDE and WATER) so the HEART is now pumping blood around the body at a faster rate in order to provide these cells with what they need. To summarize, the circulatory system has to work harder and faster during exercise to provide the cells at work with glucose and oxygen and to get rid of the waste carbon dioxide.
What is happening to her breathing system?
{Relates to explanation given} The requirement for oxygen is increased so now the respiratory system (in particular the LUNGS) have to work harder and faster to take in more oxygen and to exhale more CO2, thus you begin to breathe faster. To summarize, oxygen is inhaled quicker and carbon dioxide is exhaled quicker, therefore the rate of DIFFUSION is increased.
Diagram:
Draw picture of a girl playing football and then in the nest picture of her lungs and heart, you can also include arteries and the veins. Show how the lung and the heart work more harder during the exercise or when playing any sports
hope this helps.....
have a great day ahead :)