Answer the following question given this paragraph: 

Many animals go through daily cycles. Daily cycles of behavior are called circadian rhythms. For example, most animals go to sleep when the sun sets down and wake up when the sun rises. These animals are active during the day and called diurnal. Other animals go to sleep when the sun rises and wake up when the sun sets. These animals are active during the night and called nocturnal. Many owls, like the owls in Figure below , are nocturnal. Like some other nocturnal animals, they have large eyes that are specially adapted for seeing when light levels are low.


Q: What term refers to an animal that sleeps during the day and is active at night?

 Choices:

- diurnal

- crepuscular

- solitary

- nocturnal

A:
nocturnal
