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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 percent...
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Metals And Non- Metals (Question Answer)

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Metals And Non- Metals (Question Answer)  QUESTIONS    1. Give an example of a metal which  (i) is a liquid at room temperature.  (ii) can be easily cut with a knife.  (iii) is the best conductor of heat.  (iv) is a poor conductor of heat.  Answer:   (i) A metal   liquid at room temperature is Mercury.                    (ii) Metal that can be easily cut with knife is Sodium.                    (iii) Metal which is best conductor of heat is Copper.                    (iv) Metal which is poor conductor of heat is M ercury. 2. Explain the meanings of malleable and ductile. Answer:  Malleability:  Metals can be beaten into thin sheets. This property is called malleability. Gold and silver are the most malleable metals.  Ductility:  The ability of metals to be...
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Metals And Non-Metals

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Metals And Non-Metals  Metals Elements which are generally solid at room temperature and which forms positive ions by releasing electron from its outermost shell are called metals. Some examples of metal are- iron, copper, gold, mercury etc.  Physical Properties of metals 1. Lustre:  Metals, in their pure state, have a shining surface. This property is called metallic lustre. 2. Hardness: Metals are generally hard. The hardness varies from metal to metal. 3. Malleability: Metals can be beaten into thin sheets. This property is called malleability. Gold and silver are the most malleable metals. 4. Ductility: The ability of metals to be drawn into thin wires is called ductility. Gold is the most ductile metal. 5. Thermal and electrical conductivity:   Metals are good conductors of heat & electricity. The best conductors of heat are silver and copper. Lead and mercury are comparatively poor conductors of heat. 6. Melting Point: Metals have high melting point...
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