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n. The duration of an organism's daily exposure to light, considered especially with regard to the effect of the exposure on growth and development.

n. The normal duration of natural daylight experienced by an organism; daylength

"Taken together, our findings suggest that optimization of experimental conditions such as photoperiod may be necessary to visualize FAA in genetically modified mice."

circadian rhythm   

photoperiodism   

Chün    reassembling    landholdings    trapezium    feudality