Which is the most efficient way for some desert plants to conserve water?

A. By having no leaves, so water evaporates from the green stem with less surface
B. By loading organic compounds in the phloem of the roots
C. By accumulating salt within their tissues, so water is retained by osmosis
D. By growing long hair on their surface, so air moisture is absorbed at night

A

This question was poorly worded but most candidates had the correct answer A. This is obviously the most correct answer, as the most extreme xerophytes have modified their leaves and transpire through their stem. It is true that some xerophytes accumulate salt, but they are not the majority. It is not right to say that moisture is absorbed at night.