Final answer:
In generations 0 to 23 of the lung's branches, both the flow of air and the linear velocity decrease due to the decrease total cross-sectional area that distributes the airflow among more branches.
The correct answer is D.
Step-by-step explanation:
From generation 0 to 23, it is known from the principles of pulmonary physiology that the flow of air decreases as it goes down the generations due to the increasing total cross-sectional area. However, the linear velocity also decreases because as the cross-sectional area increases, the flow of air is distributed among more branches, thus reducing the velocity of the air flow in each individual branch.
Therefore, the correct answer to the question 'Going from generation 0 to 23, the flow of air (L/s) ___________ and the linear velocity (cm/s) _________________' would be d) Decreases, decreases.