Short Answer TypeWhy should biodegradable and non-biodegradable wastes be discarded in two separate dust bins?
“A ray of light incident on a rectangular glass slab immersed in any medium emerges parallel to itself.” Draw labelled ray diagram to justify the statement.
“The chromosomes number of the sexually reproducing parents and their offspring is the same.” Justify this statement.
We often observe domestic waste decomposing in the by-lanes of residential colonies. Suggest ways to make people realize that the improper disposal of waste is harmful to the environment.
List and explain any two advantages associated with water harvesting at community level.
Write the name and the structural formula of the compound formed when ethanol is heated at 443 K with excess of cone. H2SO4. State the role of conc. H2SO4 in this reaction. Write chemical equation for the reaction.
Why homologous series of carbon compounds are so called? Write chemical formula of two consecutive members of a homologous series and state the part of these compounds that determines their (i) physical properties, and (ii) chemical properties.
Given below are some elements of the modern periodic table: 4Be, 9Fe, 14Si, 19K, 20Ca
(i) Select the element that has one electron in the outermost shell and write its electronic configuration.
(ii) Select two elements that belong to the same group. Give reason for your answer.
(iii) Select two elements that belong to the same period. Which one of the two has bigger atomic size?
Write the number of periods the modern periodic table has. How do the valency and metallic character of elements vary on moving from left to right in a period? How do the valency and atomic size of elements vary down a group?
(a) Explain the process of regeneration in Planaria. (b) How is regeneration different from reproduction?
Regeneration in Planaria
Regeneration is the process in Planaria, by which any part of the body if cut, is capable of developing into a complete organism. Regeneration is carried out by specialized cells. These cells proliferate and make large numbers of cells and from this mass of cells, different cells undergo changes to become various cell types and tissues. These changes take place in an organized sequence referred to as development and finally lead to the development of a complete organism.
b.
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Regeneration |
Reproduction |
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1. It is a type of asexual mode of reproduction in which only single parent is involved |
1. It includes both sexual and asexual mode of reproduction in which either single parent or both the parents are involved respectively. |
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2. This mode of reproduction depends on the fact that the organism needs to be cut in order to regenerate. |
2. This mode of reproduction is not dependent on cut. |
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Example- Planaria |
Example- Sexual reproduction in humans |
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