The correct answer is - cyanobacteria.
The atmospheric oxygen came from the cyanobacteria. These were one of the earliest living organisms on Earth. The cyanobacteria was using photosynthesis in order to create its own food. The photosynthesis process requires sunlight, carbon dioxide, water, and oxygen. The oxygen is mostly released as a waste product from the process of photosynthesis, thus the cyanobacteria were literally releasing oxygen that was ending up into the atmosphere. As more and more cyanobacteria there were across the planet, more and more oxygen they were releasing into the atmosphere, slowly changing the composition of the atmosphere, and setting the basis of it as we know it now.
Answer:
C
Explanation:
When immigrants arrived to the East Coast of the United States in the 19th Century, they tended to move into neighborhoods in which members of their nationality already lived.
This was practical as the immigrants would be able to assimilate easier and would not feel as isolated in the new country. The established immigrants could also be a useful source of information and could help in difficult times.
These neighborhoods were located in the large East Coast cities and came to be small representations of the home country of the immigrants that founded them.
Answer:
Triangulation method
Explanation:
- In triangulation method Scientist s take a paper.
- The sesmometers which are established in that area is shown as green dots.
- The calculated distance from each seismometer to the earthquake is shown as a circle.
- The point where all circles intercept eachother is known as the epicenter of the earthquake.
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- Their are many plates moving inside earth's surface.
- When the plates collide with eachother a friction arises which is called earthquake.
