Radio telescope picks up the radio spectrum of electromagnetic waves from celestial bodies (just like telescopes like the Hubble pick up visible light – only that radio waves are invisible to our eyes). They are therefore used to detect objects in space that produces radio waves. Examples are quasars and pulsars. Radio telescopes also enable astronomers to be whats beyond gas and dust in space that blocks out most of the visible light spectrum.
Out of the following given choices;
a. they increase the amount of energy transferred from the
lungs to the blood
b. they increase the flexibility of the lungs as they expand
during inhalation
c. they increase the volume of the lungs, allowing more
oxygen to be inhaled
d. they increase the surface area of the lungs, allowing the
efficient gas exchange
The answer is D. Due to their microscopic nature, they are numerous in the lungs and are also circular-shaped so as to increase the surface area for gaseous exchange.
Other characteristics of alveoli that increase gas exchange are that they thinned-walled (with only a layer of cells) and moist.