1. Atomic no. of x = 12; Atomic No. of y = 16
2. The transfer of traits from parents to offspring is called heredity.
3. Paper and glass can be easily recycled but thrown in the dust bin.
4. This is because both the father and the mother contribute practically equal amounts of genetic material to the child during sexual reproduction in forming ztgote.
5. Object placed between pole and focus see in diagram:
6. Decomposer break-down the complex organic substances into simple inorganic substances. The natural replenishment of the soil also takes place by Decompose.
7. Watershed management is the study of the characteristics of a watershed. It helps to manage water quality, water supply, and drainage and rainwater flow. It also ensures sustainable maintenance planning of a watershed.
Benefits of a watershed management system:
Water quality is strictly maintained.
Distribution of water is equal and sustainable.
8. The producers convert solar energy into chemical energy in the form of organic compounds. The primary consumers (herbivores) derive their nutrition from the producers.
A large number of pesticides and chemicals are used to protect our crops from pests and diseases. Some of these chemicals are washed down from the soil, while some enter the water bodies. From the soil, they are absorbed by plants along with water and minerals; and from the water bodies, they are taken up by aquatic plants and animals. As
25. (C) Convex lens of focal length 20 cm.
26. (B) Concave and F > F
27. (D) 2, 3 and 4
28. (C) 20 cm on the other side of the lens and is of the same size, real and inverted.
29. (D) Y, Q and P
30. (B) Q
31. (C) ∠r only
32. (C) III
33. (A) Plumule, Cotyledon, Radicle
34. (D) Radish and carrot
35. (C) III and IV
36. (C) III, II, I, IV
37. (B) II, I, IV, III
38. (A) 2, 3 and 5
39. (D) I, II and IV
40. (B) the ethanoic acid dissolves readily in water.
41. (C) White pellets/flakes
42. (A) the reaction is exothermic and the reaction mixture is acidic.