The brain structure which monitors his thirst and the need to drink more
water is Hypothalamus.
<h3>What is the Brain?</h3>
This organ is located in the head region of most organisms and serves as
the center of the nervous system.
It has some tissues in which hypothalamus is among which helps to
regulates body temperature, sleep, and appetite. Body temperature is
regulated by drinking water to prevent dehydration.
Read more about Hypothalamus here brainly.com/question/1022285
On a very simple level, the answer should be that archaebacteria developped in climates, atmospherical conditions, temperatures, physical and chemical environments that were in some ways different from those that characterize Earth today. So, it is reasonable that planets with conditions like those of Earth when archaebacteria developped might bear some form of life similar to archaebacteria, or evolved from those organisms.
Because it the answer that it can help you if you get op