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.
The active site’s primary function is to bind with the substrate molecule to undergo a chemical reaction.
1. spines to protect plants against animals seeking water.
2. A waxy coating on leaves to reduce water loss.
More pesticide-resistant insects. just like bacteria and viruses, insects are growing immunity's to pesticides thus stronger pesticides are needed. <span />
Answer:
If the salts are not filtered from the transpiration stream, they can damage the plant.
If excluded by the root, the salts can make it harder for the root to extract water from the soil.
Explanation:
When soil has high salt concentration, it becomes very difficult for the plant to take in water. Sometimes the problem becomes so peculiar that plant becomes completely unable to take in the water and hence they wilt and die. This happens even when the surrounding soil has sufficient water but remains un-drawn by the plants due to its high osmotic potential resulting due to highly concentrated salt solution. Therefore, more energy and effort is required by roots to extract water from salty sand.
Also if the salt concentration with in the plant increases, it remains there and causes damage
Hence, correct options are
If the salts are not filtered from the transpiration stream, they can damage the plant.
If excluded by the root, the salts can make it harder for the root to extract water from the soil.
