Ventilation systems are needed in a <span>multicellular organism to actually obtain oxygen and give out carbon dioxide. Without this ventilation system, it would be very difficult for multicellular organisms to survive. It has been also observed that surface diffusion is not enough for a multicellular organism to breath.</span>
B. Solar system galaxy universe Earth
A seascape rock is one made of metaphysical and biological properties usually of fine grained sandstone sediments.These rocks are mostly featured for decorative purposes in seascape photography.
Plants get carbon dioxide<span> from the air through their </span>leaves<span>. The </span>carbon dioxide<span>diffuses through small holes in the underside of the </span>leaf<span> called stomata.</span>
The answer is 20 because in the passage the autor said .
