$3$ Points

Time$-$series models may exhibit $$easonal effects or cyclical effects. A seasonal effect differs from a cyclical effect in that a seasonal effect:

$$ Is one that repeats at fixed intervals of time, typically a year, month, week, or day.

Describes ups and downs over a time frame such as several years.

is based on analysis of historical time$-$series data and are predicated on the assumption that the future is an extrapolation of the past. $$ Has no trend, is relatively constant, and only exhibits random behavior.