Question

question 16 of 25
how does material move from the respiratory system to the circulatory system?
a. by diffusing across a membrane
b. by moving across a synapse
c. by sending hormones between cells
d. by attaching neuroendocrine cells

Explanation:

In the respiratory system, oxygen diffuses across the alveolar - capillary membrane into the blood (circulatory system). This is a passive process based on concentration gradients. Synapses (B) are related to neural communication. Hormones (C) are mainly for endocrine system signaling. Neuroendocrine cells (D) are not the mechanism for respiratory - circulatory material transfer.

Answer:

A. By diffusing across a membrane