1. Air enters the nostrils.
2. Air passes from the trachea to the bronchi
3. Air diffuses from the alveoli to the blood cells.
4. Oxygen enters the blood cells.
5. Blood transports oxygen to other cells.
The best way for adolescent to build and protect his or her bones is to ingest food products that are rich in calcium for it is known to make bones stronger. Another way is to be able to do exercise as a daily routine so that the bones are exercised every day to prevent bone disease, this will stenghten the bones and make them more stronger.
Answer:
I think its B: Sliding filament mechanism
Explanation: