Translation of "biological clock" into Japanese

Until now, it has always been assumed that the human biological clock is regulated by cells in the retina.

これまで人間の体内時計は,網膜の細胞が調節しているとされてきた。

Many migrating birds not only have compasses in their heads but they also have biological clocks.

多くの渡り鳥は,頭部に羅針盤を持っているだけでなく,生物時計も持っています。