<u>Answer:</u>
Cyanobacteria start producing pure oxygen around 200 million years ago.
<u>Explanation:</u>
Many scientists believed that Earth did not have any oxygen. Cyanobacteria or the blue green algae are the microbes which produced oxygen for the first time with the help of photosynthesis. This was around 4.5 billion years ago: after Hadean eon.
They were very simple, but they produced oxygen in the early earth’s atmosphere. So, they brought evolution on earth. This “blue-green algae” exists in salt water, rocks and soils and play a major role in maintaining the ecosystem.
Explanation:
hope it's help you ok have a good day
A) after 1911 gradual increase in deaths pattern explains that smoking causes cancer !
b) after 2001 , the graph will continue decreasing, because of the steps taken by government, the steps by people itself !! that all helps in decreasing deaths and cancer number after 2001 !
Answer:
The cells are square
Explanation:
because they look more on the outside and I would expect them to be smaller
Make sure this is my opinion, I hope it is true
