Switch A and D, but other than that your answers are correct.
An astronomical body is an object in space.
A comet is a celestial object consisting of a nucleus of ice and a stream of gas and dust.
A moon is an astronomical body that orbits around a planet.
A galaxy is a system of start held by gravitational attraction.
b. the first stage because it could never be in the secound stage
Answer:
The alveolar membrane- is where gas exchange between the blood and the atmosphere takes place. The gas molecules must diffuse across the alveolar epithelium and the capillary endothelium. ... Thus, the alveolar surface (as well as the respiratory bronchioles) have no cilia or mucus layer.
Explanation:
hope it helps =)
