### Instruction:

Extract the cause and effect entities from the following sentence:
Nighttime is defined as the time between the end of evening nautical twilight and the beginning of morning nautical twilight

### Assistant:

VARIABLE: the time
KEYWORD: is defined as
CONDITION: between the end of evening nautical twilight and the beginning of morning nautical twilight.
EFFECT_1: Nighttime
CAUSE_1: the time between the end of evening nautical twilight and the beginning of morning nautical twilight

