A planet rotating causes cycles of day and night on that planet.
Rotation simply means how long it takes a planet to spin on its axis.
A planet spinning on its axis causes cycles of day and night on that planet.
what causes day and night cycles on a planet?

A) seasons
B) carbon dioxide
C) flow of electrons
D) gravitational pull
E) fissures of hot, acidic water
F) spinning on its axis
G) heat energy
H) energy of moving objects