Your body runs an internal clock that keeps roughly a daily cycle even in constant darkness.

What it means

Volunteers isolated from daylight and clocks settle into a cycle a little longer than twenty four hours, which shows the rhythm is generated internally rather than driven by the sun. Light resets it each morning through a set of receptors in the eye that have nothing to do with vision. Almost every tissue carries its own clock, coordinated by one master timer in the brain.

The claim comes from NIGMS.

Nearby in the collection

The facts either side of this one.

• NCBI Bookshelfeasy, 75 letters
• NCBI Bookshelfeasy, 77 letters
• NHGRImedium, 74 letters
• NHGRIhard, 67 letters

About as hard as this one

Scored closest to it by the model behind our guide to solving cryptograms.

• NCBI Bookshelfmedium, 77 letters
• NCBI Bookshelf · Molecular Biology of the Cellmedium, 74 letters
• NHGRImedium, 70 letters
• RSCmedium, 78 letters