Answer: The 3rd one, answer C
It always starts with evaporation, because without water vapor (the byproduct of evaporation), there would be no clouds (they are made out of water vapor and some other particles). Henceforth, there will be no rain.
A bone is tissue. It forms a part of the skeletal system which is made up bones, joints, ligaments and cartilage.
Cells work together in groups known as tissues. A tissue is defined as a group of similar cells working together to carry out a certain task. Examples are skin, bone, blood.
Tissues in turn are grouped together to form organs. An organ is defined as a group of tissues that work together to carry out a certain task . Examples are heart, lungs, liver.
Group IV of the Periodic Table of the Elements contains carbon (C), silicon (Si) and several heavy metals. Carbon, of course, is the building block of life as we know it. So is it possible that a planet exists in some other solar system where silicon substitutes for carbon? Several science fiction stories feature silicon-based life-forms--sentient crystals, gruesome golden grains of sand and even a creature whose spoor or scat was bricks of silica left behind. The novellas are good reading, but there are a few problems with the chemistry.
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CRYSTALLINE CREATURES? Silicon can grow into a number of lifelike structures, but its chemistry makes it unlikely that it could be the basis for alien life-forms.</span>
Indeed, carbon and silicon share many characteristics. Each has a so-called valence of four--meaning that individual atoms make four bonds with other elements in forming chemical compounds. Each element bonds to oxygen. Each forms long chains, called polymers, in which it alternates with oxygen. In the simplest case, carbon yields a polymer called poly-acetal, a plastic used in synthetic fibers and equipment. Silicon yields polymeric silicones, which we use to waterproof cloth or lubricate metal and plastic parts.
