Until 1985 all commercial airlines

Answer choices

1. A

   Unsupported Causal Speculation5% picked this

   In 1985 there was a loosening of regulations concerning cabin air in

   We don't know why the rate of replenishing changed. It might be because of regulatory changes, but that's just as supportable as any other hypothesis (f.e. the airlines wanted to save money)

   5%
2. B

   Less Provable than Correct Answer25% picked this

   People who fly today are more likely to contract airborne illnesses than were people who

   This is a very tempting answer, because it goes along with the gist of what we were told about air in the cabin, but it's not a must be true. There are more factors than just air replenishment that can affect likelihood of contracting an airborne illness. Has the average health of passengers changed? Do passengers wear masks more than they used to? Are passengers less likely to fly with germ-ridden children than before? If there weren't a rock-solid provable answer available, then we would certainly pick this.

   25%
3. C

   Too Strong: impossible1% picked this

   Low levels of carbon dioxide in cabin air make it impossible for airborne

   We know that lower levels of CO2 make it harder for airborne illness to spread, but we can't do this Relative vs. Absolute switch and say, when there's low CO2, there's zero risk of spreading airborne illness.

   1%
4. D

   Out of Scope5% picked this

   In 1980 the rate at which the cabin air was replenished in commercial airliners was sufficient to protect passengers from the

   Out of Scope: effects of CO2 buildup The passage never discusses "the effects of CO2 buildup". We know one effect of CO2 buildup (easier for airborne illnesses to spread), but there maybe others as well (foggy thinking, fatigue). We don't know if the pre-1985 replenishment rate suppressed CO2 buildup so much that passengers were protected from all of its possible effects. We wouldn't even say that pre-1985 passengers were protected from airborne illnesses; we would just say they were better-protected than in post-1985.

   5%
5. E

   Correct65% picked this

   In 1980 the level of carbon dioxide in the cabin air on a two-hour commercial airline flight was lower than it is

   Why this is right

   On a two hour flight in 1980, the air would be replenished at least 3 times 30 mins in, 60 mins in, 90 mins in On a two hour flight today, the air would be replenished 1 time 60 mins in We have a rule that says "the less frequently it's replenished, the higher the level of CO2 in the plane". So that means that a two hour flight today would have a higher level of CO2 than would have a two hour flight in 1980. (you could say it's also replenished at the 2 hour mark, when the flight is over, but that would still mean 4 replenishments for 1980 and 2 replenishments for today)

   Skill tested: Most Supported · how this choice captures the argument's function is the move to repeat next time.

   65%