Answer:
The correct answer is option b, that is, four-field approach.
Explanation:
Anthropology refers to the study of human beliefs, behavior, and adaptations. In order to completely comprehend any aspect of human behavior, the field of anthropology adopts a four-field approach. The four sub-disciplines of anthropology are archaeology, cultural anthropology, biological anthropology, and linguistic anthropology.
In archaeology, materials are used generally from past cultures, in order to understand and illustrate human behavior and adaptive strategies via time. Biological anthropology refers to the study of humans as biological species, the research areas comprise diversity in modern human populations, human evolution, and medical anthropology.
The cultural anthropology explores patterns of behavior and belief in historical and contemporary cultures all over the globe. The linguistic anthropology studies and documents languages in terms of acquisition, structure, and use in the transmission of culture. As can be seen that each of the sub-disciplines focuses on distinct characteristics of human adaptation, however, when taken together in a four-field approach it offers a powerful tool for gaining a complete understanding of any aspect of human behavior.
Answer:
The preceding section reviewed the major metabolic reactions by which the cell obtains and stores energy in the form of ATP. This metabolic energy is then used to accomplish various tasks, including the synthesis of macromolecules and other cell constituents. Thus, energy derived from the breakdown of organic molecules (catabolism) is used to drive the synthesis of other required components of the cell. Most catabolic pathways involve the oxidation of organic molecules coupled to the generation of both energy (ATP) and reducing power (NADH). In contrast, biosynthetic (anabolic) pathways generally involve the use of both ATP and reducing power (usually in the form of NADPH) for the production of new organic compounds. One major biosynthetic pathway, the synthesis of carbohydrates from CO2 and H2O during the dark reactions of photosynthesis, was discussed in the preceding section. Additional pathways leading to the biosynthesis of major cellular constituents (carbohydrates, lipids, proteins, and nucleic acids) are reviewed in the sections that follow.
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Carbohydrates
In addition to being obtained directly from food or generated by photosynthesis, glucose can be synthesized from other organic molecules. In animal cells, glucose synthesis (gluconeogenesis) usually starts with lactate (produced by anaerobic glycolysis), amino acids (derived from the breakdown of proteins), or glycerol (produced by the breakdown of lipids). Plants (but not animals) are also able to synthesize glucose from fatty acids—a process that is particularly important during the germination of seeds, when energy stored as fats must be converted to carbohydrates to support growth of the plant. In both animal and plant cells, simple sugars are polymerized and stored as polysaccharides.
Gluconeogenesis involves the conversion of pyruvate to glucose—essentially the reverse of glycolysis. However, as discussed earlier, the glycolytic conversion of glucose to pyruvate is an energy-yielding pathway, generating two molecules each of ATP and NADH. Although some reactions of glycolysis are readily reversible, others will proceed only in the direction of glucose breakdown, because they are associated with a large decrease in free energy. These energetically favorable reactions of glycolysis are bypassed during gluconeogenesis by other reactions (catalyzed by different enzymes) that are coupled to the expenditure of ATP and NADH in order to drive them in the direction of glucose synthesis. Overall, the generation of glucose from two molecules of pyruvate requires four molecules of ATP, two of GTP, and two of NADH. This process is considerably more costly than the simple reversal of glycolysis (which would require two molecules of ATP and two of NADH), illustrating the additional energy required to drive the pathway in the direction of biosynthesis.
Vitamin niacin ( vitamin B3)
When a human dies, his corpses gets decomposed by decomposing bacteria. What's produced by the decomposing bacteria is the "fertilizer" for plants.
