D. eye that's the answer
hope this helped
Answer:
genetic factors, long-term physical health conditions, and head injuries or epilepsy.
Explanation:
Measure your heart rate before, during and after work outs and write it down. Monitors can be worn as a strap across the chest, on the wrist and even on the head, and by measuring your heart rate can help you exercise at the right intensity. Most don't have a display, so you'll need to connect your monitor with a sports watch or smartphone app to see your heart rate.