Circulation of the air, letting outside air in and air filters.
Answer:
for examples: you are riding a bike before you ride a bike wear you gear first.
because gears can helps you from getting injury.
for another examples: you are on the road to don't get injury or anything you need to follow all the rules and beware of any situation that can happen in the road.
The best answer for the blood vessels' valves would be these are veins that would then help in preventing the back flow of blood because the walls have small muscle to pump the blood back to the heart.Hope this is the answer.
Answer:
Explanation:
I had really good success with a low-carb, high protein diet. The two biggest dieting tips I've found are to invest time into food prep so you have meals that are easy to make and it's easier to not say "I don't feel like cooking, I'm gonna go to McDonalds" and to keep healthy snacks around (I like raw veggies, roasted chicken, and sugar-free jello) because it's a lot easier to eat healthy snacks than to force yourself not to eat. I've also found a crock pot to be an invaluable tool for dieting because it's super easy to quickly make healthy meals with one.
