I would say the left atrium of the heart
Basically, the disadvantages of a green roof are listed in the last sentence:
<span>"However, green roofs can be expensive to install, and require care and maintenance"
The disadvantage of a green roof would be there for the owners: the cost and time needed to have such a roof.
An additional disadvantage would be the possibility of the plants on the roof mixing with and replacing the local vegetation, thus diminishing the biodiversity in this place.
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The third one is the product of cellular respiration
The defense system of the human body is made up of entire organs and vessel systems like the lymph vessels, but also of individual cells and proteins. The inner and outer surfaces of the body are the first barriers against pathogens (germs). These surfaces include the skin and all mucous membranes, which form a kind of mechanical protective wall.
Several things support this protective wall:
<span><span>- The body’s own antibacterial substances can disable different pathogens from the environment at an early stage. A certain enzyme found in saliva, the airways and tear fluid destroys the cell walls of bacteria.
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- Many pathogens that are breathed in get stuck to mucus in the bronchi and are then moved out of the airways by hair-like structures called cilia.
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- Most pathogens that enter the body together with food are usually stopped by stomach acid.
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- Normal flora, harmless bacteria that reside on the skin and many mucous membranes in the body, also help to protect the body.</span></span>
The cough and sneeze reflex can also help to remove pathogens.
Hope this helps (:
The answer is C because C represent plants and plants produce oxygen and absorb CO2
