Answer: d. the wind
Wind is not a land resource. It is the natural movement of air across the earth surface. Wind is also considered as movement of gases present in the atmosphere. The strength and direction of wind can be measured. It is a atmospheric resource. Wind produces as a result of difference in the atmospheric pressure. When a difference in atmospheric pressure exist air moves from region of high pressure to low pressure area. Wind energy is renewable source of energy can be used to produce electrical energy.
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.
<span>
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.
Answer:
Pesticides used in mosquito control can contribute to immune suppression in humans. A report from the World Resources Institute notes, "Impairment of the immune system by chemical pesticides can lead to allergies, auto immune disorders such as lupus, and cancer.
Explanation:
