Sunflowers follow the Sun throughout their entire life.
Why it is true
Young sunflowers exhibit heliotropism, turning their heads to follow the Sun from east to west. At night, they turn back to face east. When they mature, they stop following the Sun and remain facing east.
Source: Scientific American
Would you rather be asked first?
This is the reading side of the site, so the answer is in the sentence above — that is the whole point of it. Test yourself works the other way round: the question comes on its own, and the fact and the explanation only appear once you have answered.