Until 1985 all commercial airlines completely replenished the cabin air in planes in flight once every 30 minutes. S...

Ravi on July 24, 2019

@zgnewquist,

Happy to help. Let's take a look at (C) and (E).

(C) says, "Low levels of carbon dioxide in cabin air make it
impossible for airborne illnesses to spread."

(C)'s wording is far too strong to be supported by the stimulus. We
know high levels of carbon dioxide make it easier for airborne illness
to spread, but we have no idea if low levels make it impossible for
airborne illnesses to spread. We can infer that it's less likely, but
we can't infer that it's impossible, so (C) is out.

(E) says, "In 1980 the level of carbon dioxide in the cabin air on a
two-hour commercial airline flight was lower than it is today on a
similar flight."

Assuming everything else is equal, the more frequent replenishment
taking place prior to 1985 would allow for comparatively lower levels
of carbon dioxide than on flights today. We know that prior to 1985,
flights replenished air every 30 minutes. 1980 is before 1985, so
flights that occurred in 1980 would have replenished air every 30
minutes, so (E) is strongly supported by the stimulus.

Does this make sense? Let us know if you have any more questions!

zgnewquist on September 25, 2019

Ok awesome, that is very helpful. Thank you!