The alveoli are lined with mucus and are surrounded by a network of blood capillaries. They have very thin walls for gases to be absorbed through. An individual air sac is called an alveolus. The layer of moisture in the alveoli allows gases to dissolve so that they can diffuse quickly.
The answer to this question is : <span>They tolerate both freshwater and salt water.</span>
The answer is population I think
Metrology. evolution biology
Answer:
B
Explanation:
Igneous rocks are formed by the solidification of magma or lava.
