Answer:
Crust- ranged from 6km to70km thick .
mantle- convection here leads to earthquakes.
Core -has a liquid and soild layer
Moho barrier- separates the crust and mantle.
Explanation:
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The major function of the immune system is to protect the host from environmental agents such as microbes or chemicals, thereby preserving the integrity of the body. This is done by the recognition of self and response to non-self.
<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.
Answer: do u speak English
Explanation:
