We are shorter in the morning than at night.
Why it is true
We are about 1 to 2 centimetres taller when we wake up than when we go to bed. During the day, the body's weight compresses the water-rich intervertebral discs of the spine. On waking, after hours lying down without compression, a person is taller.
Source: NIH
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.