A virus is a microscopic particle that can infect the cells of a biological organism. Viruses can only replicate themselves by infecting a host cell and therefore cannot reproduce on their own. It has been argued extensively whether viruses are living organisms.
The ocean and the present atmosphere themselves are not leftovers from the original atmosphere of Earth. However, they do contain components within them that give us and scientists ideas of what Earth's past atmosphere was like.
Some example include:
1) Ice cores - scientists may go to Antartica or Alaska and stick this metal tube into the ice to remove what is known as an "ice core". This is then taken back to the lab for analysis. So what happens is that this ice as we know is constantly melting and freezing with different seasons and climate change. So, when the ice starts to crystallize, particles like carbon dioxide, sulfur etc may get trapped as bubbles in the ice. This is what scientists look for in ice coring and this is how they know that Carbon dioxide levels were relatively high back then (Not as high compared to now).
2) Ocean sediment cores - this is the exact same process of the ice cores except they take cores of sediments (esspecially calcium carbonate that contains oxygen). As you know, CaCO3 is found in the exoskeletons of organisms that die and build up on the ocean floor.
Those are some of the main ways that the present atmosphere and oceans have leftovers from the original atmosphere of Earth.
Hope that helped!
In this item we are given that the methane emission rate will go high due to the foreseen temperature rise cause by global warming. The biogeochemical cycle that will be affected directly through this is the Carbon cycle.
Methane is a compound comprised of one atom of carbon and four atoms of hydrogen. Carbon cycle involves the process in which the carbon dioxide emitted by the organisms will be absorbed by the producers. The carbon which are to be absorbed by producers should come in the form of carbon dioxide.
