15) A

Reasoning made in argument:

Earth got water from dust cloud or meteorites. Since less deuterium is found in water on Earth than in meteorites, Earth got its water from dust cloud.

A – Correct

Compare soil to earth, dust cloud or meteorites to acidity and alkalinity and camellias to deuterium. Since there are camellias growing here, which cannot tolerate alkalinity (less deuterium on Earth than in meteorites), the soil must be acidic (Earth must have gotten its water from the dust cloud).

B – Wrong

This statement is not of the same reasoning because there is an obvious answer to ‘Were the dinosaurs warm blooded or cold blooded?’. There was not an obvious answer as to where the Earth got its water. Research had to be done before any conclusion could be made

C – Wrong

There is no evidence that life exists on them. This reasoning is wrong as it is just assuming that since a Goldilocks planet is neither too hot nor too cold and there are many of them in the Universe, there must be life on them.

D – Wrong

This option states that “Most people travel by bus”. This suggests that there are some people that travel by taxi. So people do reach the airport by both taxi and bus. However, Earth can only get its water by either dust cloud or meteorites and not both.