When a bend in a river gets cut off...
Answer;
Retinohypothalamic path
A small branch of the optic nerve, known as the retinohypothalamic path extends directly from the retina to the SCN.
Explanation;
The SCN is an abbreviations for suprachiasmatic nucleus or nuclei; which is a region in the hypothalamus. that is responsible for controlling circadian rhythms.
Retinohypothalamic path is a neural input pathway that extends directly from the retina to the SCN.
Buildup of organisms means that the species number is pretty high.
Gradual change means that it was a slow, calm time to make the change.
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Eye strain - hope this helped