Multi cellular organisms like animals are eukaryotes
1) put some form of lubrication like oil or water in front of the block so that it can slide easier.
I’m not sure about the second one sorry x
The bird was frightened by the human as a defense mechanism it knows to fly away for safety.
Answer:
The alveoli are sacks coated on their inner wall by white and sticky liquid, they can be more than a millimeter in diameter and surface active agent. In them there is the exchange of gases between O2 and CO2.
They are evaginations of the epithelium of the air ducts with a single opening for the gases to exit and enter, controlled by the action of a smooth muscle sphincter. Its walls, called alveolar septa, provide a large increase in the exchange surface.
