Circannual rhythm in an organism is A) regulated by photoperiod B) an innate character C) regulated by temperature D) an acquired character Which one of the following is/are correct?

A circadian rhythm is any biological process that displays an endogenous oscillation of about 24 hours. These rhythms are driven by a circadian clock, and rhythms have been widely observed in plants, animals, fungi and cyanobacteria. The term circadian comes from the Latin circa, meaning around and diem or dies, meaning day. The rhythm is linked to the light–dark cycle that is photoperiod. Circannual rhythm in an animal is an adaptive character developed by the animals in response to the frequent changes in the environment.