PLEASE ANSWER QUICK!! I WILL GIVE BRAINLIST! Which of the following body systems involves the heart, blood, and blood vessels?
A) Respiratory system
B) Endocrine system
C) Circulatory system
D) Neurological system

Rachel wants to improve her body composition by reducing her bmi. she swims with her friends after school two days a week and eats a well-balanced diet. what else should she do to ensure that she properly applies all the necessary fitt principles in her plan? a. she should add more cardiovascular training and weight training to her exercise routine and eat several low-calorie meals throughout the day. b. she should increase her swimming workouts to five days a week and eat a high-calorie diet that equals 2,500 calories. c. she should add a few days of weight training to her exercise routine and consume 4,000 calories a day. d. she should eat a high-protein, low-carbohydrate diet and add five days of weight training to her exercise routine. select the best answer from the choices provided. a b c d mark this and return