Answer:
air is drawn into the lungs
lungs expand
the muscles between the ribs contract to move the ribs up and down
air pressure in the chest cavity decreases
the diaphragm contracts and flattens
Answer: Skeletal system Explanation:
I'd have to say it'd be the dramatic increase in the diversity of the population gene pool.The increased diversity can lead, in time, to a dramatic increase in the number of distinct species in an environment.
Answer:
Amphibians
Explanation:
They had just shown up during the Carboniferous period and were still living in the water.
Answer:
20 newtons
Explanation:
You have to subtract the smaller force from the larger since the forces are being pushed in opposite directions.
