<span>Circadian rhythm</span>, also known as circadian clock or body clock is a biological process that follows a 24 hour cycle (approximately). It is said that circadian rhythm is dictated by natural factors in the body, as well as environmental signals.
A neighborhood with a mayor and people working to better the town
This example reflects the food chain.
<span>The food chain describes relationships among the organisms by showing how the organisms are related to each other by the food they eat. The food chain contains levels and each of them presents a different trophic level (position of the organism in that chain). There is reliable energy transfer through each stage of the chain. Not all the energy at one stage is absorbed by the organism at the next stage but, the amount of energy from one stage to another decreases.</span>
Schwann - In 1839, he cells are the basic unit of animal structure
Schlieden - In 1838, he discovered cells are the basic unit of plant structure
Hope this helps
