If the inner lining of the air sacs neither thin nor highly vascularized, then it can be inferred that AIR SACS ARE CANNOT BE THE SITES OF GASEOUS EXCHANGE BETWEEN AIR AND BLOOD. Air sacs are generally lined with mucus and surrounded with blood capillaries.
In case of birds, air sacs play an important role in respiratory system.
Answer:
Tundra Biome and the Deciduous Forest Biome
Explanation:
for tundra the features are Extremely cold climate, Low biotic diversity ,Simple vegetation structure. and for deciduous forest is Deciduous forests have a long, warm growing season as one of four distinct seasons, There is abundant moisture, Tree leaves are arranged in strata: canopy, understory, shrub, and ground.
A. They impede fish migration and spawning
