I believe that it's an exhausted bear. Cellular respiration is the way plants and animals receive energy. If the bear is exhausted, it means it's cellular respiration is lacking.
Both answers C. and D. are correct. Most marine animals live in pods like seals, whales, and walrus. A. is called a school of fish while B. is a colony of penguins. :(
Answer: It helps to regulate circadian rhythm
Exposure to natural light during the day helps regulate the circadian
rhythm, which improves sleep pattern. The term circadian rhythm refers to our
biochemical, physiological and behavioral processes in approximately 1 full day
cycle. Circadian rhythm plays an
important role in
controlling when we fall asleep and when we wake up.
During day light, the secretion of melatonin or sleep hormone is
suppress by melanopsin that keeps people awake and alert. Nevertheless, during nighttime,
melanopsin stimulates the release of melatonin to signal sleeping time. Therefore,
this hormone works the entire day and has direct effect on the circadian
rhythm, which acts as a regulator of our biological clock.
Stimulants are substances that all result in the increase of levels of dopamine in the brain, which is a neurotransmitter that affects attention and pleasure. What this means is that stimulants affect our brain and the way it works by changing the ways that nerve cells communicate.
Neurons (nerve cells) are the cells that have a role in transmitting messages from the brain to other parts of our body, and vice-versa, which is important for pain response, alertness, energy etc.
With long-term use, the use of stimulants would affect the central nervous system (speeding it up), the brain, and the functions necessary to live, like respiration, heart rate, blood pressure, body temperature. Levels of neurotransmitters like dopamine, serotonin, and GABA, which are responsible for the regulation of different processes, are also impacted, which creates a chemical disbalance ultimately resulting in behavioral changes, mood swings, altered attention, movement and energy, stress etc.
So the part of the body that is affected the most with the long-term use of stimulants like cocaine, nicotine, methamphetamine is the brain of course, which is where these substances have the most impact, but the impact on the central nervous system, autonomous nervous system, and neurotransmitter levels is significant.
