The answer is d both a and b
Answer:
The upper respiratory system includes the nasal cavity (nose), the pharynx and larynx.
Explanation:
Air enters the body through the nose or mouth, this moistens and warms the air that enters since cold dry air will irritate the lungs. The air then travels down the voice box and down the windpipe.
Explanation:
The heart helps fight diseases by sending signals to either the pituitary gland or the microglia acts as a 1st responder once it senses an attack. it does this by boosting production of a molecule PCTR1, helps WBC's kill invading bacteria..
