It would be the respiratory system
Microbes. Bacteria, for example, convert nitrogen and carbon dioxide from the air into usable components that plants and animals can use as essential building blocks. A loss of all microbes would be terrible news for living organisms that can't create or take in these essential nutrients on their own.
This is called Homeostasis
Answer:
"Location 4" indicates a low-pressure area
Explanation:
A low-pressure area is defined as the region in which the pressure in the atmosphere is comparatively lesser than nearby surrounding areas. This region is a depression that is comprised of more winds, warmer air, and lifting of air mass takes place.
In a low-pressure zone, the warm air becomes less dense, due to higher temperature, as a result of which it rises up into the atmosphere. As it rises up into the atmosphere, it eventually cools and condensation starts taking place. After a definite period of time, rainfall occurs.
Thus, in the given image, location 4 shows the low pressure area.