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  Structure of the Ecosystem: Ecosystems are functional units of nature where living organisms interact with each other and the physical environment. They can vary in size from small ponds or forests to large-scale systems like the biosphere. Ecosystems can be categorized as terrestrial (land-based) or aquatic (water-based). Examples of terrestrial ecosystems include forests, grasslands, and deserts, while aquatic ecosystems include ponds, lakes, wetlands, rivers, and estuaries. Man-made ecosystems, such as crop fields and aquariums, can also exist. Input, Transfer, and Output of Energy: Ecosystems rely on the input of energy, primarily from the sun, which drives the process of photosynthesis in plants. The energy captured by plants is transferred through the ecosystem in the form of food. Energy flow occurs through the food chain or food web, where organisms consume other organisms. Nutrients, such as carbon, nitrogen, and phosphorus, also cycle through the ecosystem, facilitating...

 1. Fill in the blanks and explain the statements. a. After complete oxidation of a glucose molecules, ---- --- --- number of ATP molecules are formed. b. At the end of glycolysis, ---- --- -- molecules are obtained. c. Genetic recombination occurs in ---- -- phase of prophase of meiosis-I. d. All chromosomes are arranged parallel to equatorial plane of cell in-- -- -- phase of mitosis. e. For formation of plasma membrane,--- --- --- molecules are necessary. f. Our muscle cells perform -- -- -- type of respiration during exercise. ANS:  a. After complete oxidation of a glucose molecule, 36-38 ATP molecules are formed. b. At the end of glycolysis, 2 molecules of pyruvate, 2 molecules of ATP, and 2 molecules of NADH are obtained. c. Genetic recombination occurs in the pachytene phase of prophase of meiosis-I. d. All chromosomes are arranged parallel to the equatorial plane of the cell in the metaphase phase of mitosis. e. For the formation of the plasma membrane, phospholipid ...

SECTION -A 1.  The change in colour of the moist litmus paper in the given set-up is due to i. presence of acid ii. presence of base iii. presence of H⁺(aq) in the solution iv. presence of Litmus which acts as an indicator (a) i and ii (b) Only ii (c) Only iii (d) Only iv. EXPLANATION: (option c) litmus changes its colour in the presence of acids and bases hence act as an indicator. in the figure shown, HCl is liberated during the reaction of  NaCl and conc H2SO4 which turns blue litmus red ( acid of the solution has H+ ions) 2. In the redox reaction  MnO2 + 4HCl → MnCl2 + 2H2O + Cl2 (a) MnO2 is reduced to MnCl2& HCl is oxidized to H2O (b) MnO2 is reduced to MnCl2& HCl is oxidized to Cl2 (c) MnO2 is oxidized to MnCl2 & HCl is reduced to Cl2 (d) MnO2 is oxidized to MnCl2 & HCl is reduced to H2O EXPLANATION: (b) it is an example of redox reaction in which a substance which loses oxygen or gain hydrogen is reduced and which gain oxygen and loses hydrogen...

1. (a) Draw two different possible structures of a saturated hydrocarbon having four carbon atoms in its molecule. What are these two structures of the hydrocarbon having same molecular formula called? Write the molecular formula and the common name of this compound. Also, write the molecular formula of its alkyne.  OR  (b) (i) Write the molecular formula of benzene and draw its structure.   (ii) Write the number of single and double covalent bonds present in a molecule of benzene.   (iii) Which compounds are called alkynes?  Explanation: two possible structures of hydrocarban these structures are called isomers. isomers have the same molecular formula but different structural arrangements. the molecular formula of the alkyne is  OR i) the molecular formula of benzene is  C6H6 ii) there are double bonds and nine single bonds in benzene. iii) Alkynes are organic molecules made of the functional group carbon-carbon triple bonds and are wri...