This is Circulation !!
Pathway of the blood from Heart to Lungs to Heart then the whole body !!
The gradual abundance of oxygen (by product of photosynthesis) made it possible for aerobic organisms to grow more and evolve.
Hope that helps!
The first steps they take into consideration is where did it start, where has it spread, then they ask themselves questions is there an viruses similar to this one? Has anyone else found information on this virus? (Etc) then they probably start research by seeing who else has found info on the virus and then they might start to set up labs to conduct there own test to get a better understanding, then once all of that is done they start releasing information to people, for info I would look at the health page of your country or state or province (mines health Canada yours might be different)
Answer:
The reasons are the following.
Explanation:
Bear can live on land in a very cold regions of earth with the help of its thick skin and more hair on its body.
Frogs lives on lands due to its body structure and food availability. It has sticky tongue that captures insects.
Humans lives on lands not in water due to its body structure because its body structure can't allow humans to live in water due to absence of gills.
Seagull lives in the aquatic ecosystem because seagull feeds on fishes and other marine animals.
Sharks lives in water due to its body structure such as gills that are used to respire in water and the shark can't respire without water.
Meerkat lives in the arid climate because they lives underground to save themselves from the environment and the presence of food.
Protea lives in desert due to their dry skin that can tolerate the warm temperature.
Lions lives in the jungle due to the presence of food such as deer, buffalo etc and warm environment.
Dragonfly lives on land and water due to feed on the larva of mosquitoes that is present in the water bodies and good environmental conditions.
The atmosphere which is the lowest layer