Answer:
1 = veins
2 = cardiovascular system
3 = fibrin
4 = target heart rate
5 = maximal heart rate
Answer and Explanation:
Macros are macronutrients. Your body needs these nutrients in larger amounts in order to function properly as macro means large. In addition, all of these nutrients provide your body with energy measured in the form of calories or kcals. There are three types of macronutrients: carbohydrates, proteins, and fats. But in this case the answer is protein.
