"Plants could readily develop seasonal responses for flowering based on temperature changes but have "elected" through evolution to manage their rhythms based on a comparison of daylight and darkness. Why has the day-night ratio system been selected?"

Temperature is a gradation but day/night is all-or-nothing

Explanation:

Temperature change is progressing. I.e from Hot to cold, it moves gradually along a gradient. But Night and Day is a two edged variance. It's either day or night, also know as the All-or-nothing .

hello there are no statements below!

the answer is: trichonympha lives in the gut of termites and digests cellulose eaten by the termite.

this is an example of a symbiotic association of a protozoan with its mode of association.

hope i

-lavira: )