a, because exercise doesn't just aid the prevention of certain diseases, it helps prevent many diseases. i would've chosen d if it wasn't so specific but a is the correct answer.
Answer:
B D F
Explanation:
circulatory to get the white blood cells to where they need to go
immune to create the cells and kill the invaders
nervous to tell the body HEY GET TO WORK!!!!
<span>If you want to resolve conflicts that arise in your life, what you must have is a list of priorities. If you make such a list, you will always know what things you need to do each day, and you will always be busy, but also organized, and able to accomplish everything you want, and thus secure your happiness. This way you will avoid any conflicts that may come up during your life.</span>
