Answer:
you could disect them or observe what they do by doing things like putting them in a maze or seeing what they do in front of a mirror.
Explanation:
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:
Global warming is a change in the earth's climate which makes it heat up. While the greenhouse effect is a natural process that always is happening because of sunlight and the atmosphere.
I hope this is easy enough.
The Phytoplankton <span>support nutrients in water and from the base of many aquatic ecosystems.</span>
Answer:
Animal by-products.
The USDA (United States Department of Agriculture) defines an animal product as anything made from an animal, excluding muscle meat.
