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Heredity and Evolution (Question Answer)

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  Heredity and Evolution (Question Answer) QUESTIONS 1. If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?  Answer: B trait has arisen earlier because it exists in maximum population. 2. How does the creation of variations in a species promote survival? Answer:  The variations created in a species protects the organism from extinction even in adverse conditions. As a result, the organism gains stability. Helps to adapt to the changing environment of the natural environment. 3. How do Mendel’s experiments show that traits may be dominant or recessive?  Answer:  Mendel used a number of contrasting visible characters of garden peas – round/wrinkled seeds, tall/short plants, white/violet flowers and so on. He took pea plants with different characteristics – a tall plant and a short plant, produced progeny from them, and calculated the percentages of tall or short pr

Chemical Reactions and Equations

  Chemical Reactions And Equations Chemical Reactions:   A chemical reaction is a process in which one or more substances undergo a chemical change to form a new substance with new chemical properties.                When a chemical reaction takes place, the following changes usually occur:                          (1) Change of states                          (2) Change in colour                          (3) Evolution of gas                          (4) Changes in temperature                          (5) Formation of precipitation etc.      Example- (1) Formation of curd from milk.                          (2) Cooking of food                          (3) Combustion of magnesium ribbon in air                          (4) Rusting of iron etc. Chemical Equation:  Description of a chemical reaction in a shorter form using word or symbol is called a chemical equation.                                                  Magnesium + Oxygen → Magnesium oxide -------  is a word-equation.