Answer the following question given this paragraph: Stem Cells A stem cell is an unspecialized cell that can divide without limit as needed and can, under specific conditions, differentiate into specialized cells. Stem cells are divided into several categories according to their potential to differentiate. The first embryonic cells that arise from the division of the zygote are the ultimate stem cells; these stems cells are described as totipotent because they have the potential to differentiate into any of the cells needed to enable an organism to grow and develop. The embryonic cells that develop from totipotent stem cells and are precursors to the fundamental tissue layers of the embryo are classified as pluripotent. A pluripotent stem cell is one that has the potential to differentiate into any type of human tissue but cannot support the full development of an organism. These cells then become slightly more specialized, and are referred to as multipotent cells. A multipotent stem cell has the potential to differentiate into different types of cells within a given cell lineage or small number of lineages, such as a red blood cell or white blood cell. Finally, multipotent cells can become further specialized oligopotent cells. An oligopotent stem cell is limited to becoming one of a few different cell types. In contrast, a unipotent cell is fully specialized and can only reproduce to generate more of its own specific cell type. Stem cells are unique in that they can also continually divide and regenerate new stem cells instead of further specializing. There are different stem cells present at different stages of a human's life. They include the embryonic stem cells of the embryo, fetal stem cells of the fetus, and adult stem cells in the adult. One type of adult stem cell is the epithelial stem cell, which gives rise to the keratinocytes in the multiple layers of epithelial cells in the epidermis of skin. Adult bone marrow has three distinct types of stem cells: hematopoietic stem cells, which give rise to red blood cells, white blood cells, and platelets... Q: A stem cell is an unspecialized cell that can divide without limit as needed and can, under specific conditions, differentiate into these? Choices: - clones - infectious cells - germ cells - specialized cells A:
specialized cells
(Question)
Answer the following question given this paragraph: The surface temperature of most stars is due to their size. Bigger stars produce more energy, so their surfaces are hotter. But some very small stars are very hot. Some very big stars are cool. Q: What is the touch response in plants called? Choices: - phototropism - pollenation - sensitivity - thigmotropism A:
(Answer)
thigmotropism
Ques: Answer the following question given this paragraph: Objects such as ships may float in a fluid like water because of buoyant force. This is an upward force that a fluid exerts on any object that is placed in it. Archimedes discovered that the buoyant force acting on an object equals the weight of the fluid displaced by the object. This is known as Archimedes' law (or Archimedes' principle). For an entertaining video presentation of Archimedes' law, go to this URL:. Q: What is the upward force exerted by fluids when any object, such as a boat, is placed in it? Choices: - human force - atomic force - impetuous force - bouyant force A:
Ans: bouyant force
(Q).
Answer the following question given this paragraph: Chemical digestion occurs when large food molecules are broken down into smaller nutrient molecules. This is a chemical process that begins in the mouth and stomach but occurs mainly in the small intestine. Q: Where does the majority of chemical digestion occur? Choices: - stomach - mouth - large intestine - small intestine A:
(A).
small intestine
Ques:Answer the following question given this paragraph: Q: Much of what type of radiation that strikes the planet is reflected back into space? Choices: - magentic radiation - gamma rays - microwaves - solar radiation A:

Ans:solar radiation
Ques:Answer the following question given this paragraph: NaNO 3(s) + H 2 SO 4(l) NaHSO 4(s) + HNO 3(g) The Ostwald process is the commercial method for producing nitric acid. This process involves the oxidation of ammonia to nitric oxide, NO; oxidation of nitric oxide to nitrogen dioxide, NO2; and further oxidation and hydration of nitrogen dioxide to form nitric acid: 4NH 3(g) + 5O 2(g) 4NO(g) + 6H 2 O(g) 2NO(g) + O 2(g) 2NO 2(g) 3NO 2(g) + H 2 O(l) 2HNO 3(aq) + NO(g) Or 4NO 2(g) + O 2(g) + 2H 2 O(g) 4HNO 3(l) Pure nitric acid is a colorless liquid. However, it is often yellow or brown in color because NO2 forms as the acid decomposes. Nitric acid is stable in aqueous solution; solutions containing 68% of the acid are commercially available concentrated nitric acid. It is both a strong oxidizing agent and a strong acid. The action of nitric acid on a metal rarely produces H2 (by reduction of H+) in more than small amounts. Instead, the reduction of nitrogen occurs. The products formed depend on the concentration of the acid, the activity of the metal, and the temperature. Normally, a mixture of nitrates, nitrogen oxides, and various reduction products form. Less active metals such as copper, silver, and lead reduce concentrated nitric acid primarily to nitrogen dioxide. The reaction of dilute nitric acid with copper produces NO. In each case, the nitrate salts of the metals crystallize upon evaporation of the resultant solutions. Nonmetallic elements, such as sulfur, carbon, iodine, and phosphorus, undergo oxidation by concentrated nitric acid to their oxides or oxyacids, with the formation of NO2: S(s) + 6HNO 3(aq) H 2 SO 4(aq) + 6NO 2(g) + 2H 2 O(l) C(s) + 4HNO 3(aq) CO 2(g) + 4NO 2(g) + 2H 2 O(l) Nitric acid oxidizes many compounds; for example, concentrated nitric acid readily oxidizes hydrochloric acid to chlorine and chlorine dioxide. A mixture of one part concentrated nitric acid and three parts concentrated hydrochloric acid (called aqua regia, which means royal water) reacts vigorously with metals. This mixture is particularly useful in... Q: The ostwald process is the commercial method for producing what? Choices: - citric acid - deoxyribonucleic acid - chlorine - nitric acid A:

Ans:
nitric acid