I believe it's A, but I could be wrong. I apologize if I am so. I will do further research and get back to you
B.The embryo attaches to the mother
Air passes through is: Nostrils → nasal cavity →Pharynx → Larynx →Trachea → Bronchi (with cartilaginous rings) →Bronchioles (without rings) → Alveoli (air sacs). Alveoli are the seat of exchange of O2 / CO2 between lungs and blood.
