FAULT-TOLERANT computer systems are systems that are built with
the ability to keep working to
a level of satisfaction, even in the presence of faults within one or more of
its components. <span>This
fault tolerant ability is sometimes referred to as graceful degradation</span>
Virus: an infective agent that typically consists of a nucleic acid molecule in a protein coat, is too small to be seen by light microscopy, and is able to multiply only within the living cells of a host.
Bacteria: a member of a large group of unicellular microorganisms which have cell walls but lack organelles and an organized nucleus, including some which can cause disease.
Fungi/fungus: any of a group of spore-producing organisms feeding on organic matter, including molds, yeast, mushrooms, and toadstools.
Protozoa: a phylum or group of phyla that comprises the single-celled microscopic animals, which include amoebas, flagellates, ciliates, sporozoans, and many other forms. They are now usually treated as a number of phyla belonging to the kingdom Protista.
Decomposers, as the name suggests, decompose dead plants or animals into simple compounds. They feed on dead producers from the first levels or consumers from other three levels. Breaking them down, decomposers release nutrients that producers can use.
In an ecosystem with four levels, the first level are producers, such as plants and algae. On the second trophic level, there are primary consumers, herbivores that eat plants, for example, a deer, a rabbit, a grasshopper. The next trophic level belongs to secondary consumers that eat herbivores, for example, a wolf, a fox. The highest level is tertiary consumers that eat carnivores, for example, a bear, an eagle.
<span>Enzymes</span> are proteins that allow certain chemical reactions to take place much quicker than the reactions would occur on their own. Enzymes function as catalysts, which means that they speed up the rate at which metabolic processes and reactions occur in living organisms. Usually, the processes or reactions are part of a cycle or pathway, with separate reactions at each step. Each step of a pathway or cycle usually requires a specific enzyme. Without the specific enzyme to catalyze a reaction, the cycle or pathway cannot be completed.
