Anybody can explain why the answer is 1?

(some random idiot 4 years later from the original post of this question in the future finally corrects Jason Low. )
ok so maybe you overlook the concept of science. first of all, the leaves do not absorb water, the roots do and, secondly, even if the leaves absorbs the water, the answer would still be 4 bc if water can only be in the leaves, then what's the point? all parts of the plant needs food and water and so if the whole plant except the leaves( or should i say the roots) has water, the rest of the plant would die and leaves would not be able to produce food for the root( if you didn't know that the leaves were to make food for the plant) and the roots would die. so yeah, actually think before going to conclusions.
(actually, your not even in P5 now, so all this junk is wasted for nothing. no wonder why this was the work of a idiot)