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.
When cells communicate by the signaling process, one cell produces a signaling molecule that must be received by the signal receptor on or in the responding cell. Signaling molecules are often called ligands, a general term for molecules that bind specifically to other molecules (such as receptors).
Answer:
The answer is B the girl is wright
Answer:
How rocks change from one type to another and which processes are involved in rock changes.
Explanation:
We know that there are three types of major rocks. Those are: igneous, sedimentary, and metamorphic. The rock cycle describes how the three major rock types convert from one to another.
Changing in rocks happens as a result of natural processes that are taking place all the time. Most of the changes happen very slowly. Rocks that are in the deep within the Earth are right now becoming other types of rocks. Rocks at the surface are lying in place before they are next exposed to a process that will change them to another rock. Even at the surface, we may not notice the changes in the rocks.
Along with this, a rock cycle describes those process which involves in this rocks transformation process. It represents various environmental factors that are related to the change of the rock from one to another.
