Circadian rhythm refers to
a) the pattern of emotional ups and downs we routinely experience.
b) a pattern of biological functioning that occurs on a 24-hour cycle.
c) the experience of sleep apnea following paradoxical sleep.
d) the cycle of four distinct stages that we experience during a normal night's sleep

The correct option is B) a pattern of biological functioning that occurs on a 24-hour cycle.

Explanation:

Biological rhythm is defined as the regular variation of an organic function related to the course of time, circadian biological phenomena (around the day), are those with a period of approximately 24 hours.

Circadian rhythms are physical, mental and behavioral changes that follow a daily cycle (the biological rhythm), and that respond primarily to light and darkness in an organism's environment. This cycle close to 24 hours, allows to recognize the sleep-wake phenomena and their homeostatic action, in the systemic processes of every living being. The circadian system is composed of photoreceptors, pacemakers and efferent pathways that allow a regular functioning of the sleep and wakeful state.

it also supports my hypothesis. if you rest first you can squeeze the clothespin more times. from the data i collected the average of the eight people concluded exercise makes your muscles more fatigued and less able to squeeze the clothespin compared to resting before squeezing.

trachea, alveoli, lung capillaries, arteries