Hello hii and  15. Forests maintain oxygen and carbon dioxide balance by absorbing carbon dioxide and releasing oxygen during photosynthesis. Hello hii and 15. Forests maintain oxygen and carbon dioxide balance by absorbing carbon dioxide and releasing oxygen during photosynthesis. Hello hi and 15. Forests maintain oxygen and carbon dioxide balance by absorbing carbon dioxide and releasing oxygen during photosynthesis. Hello hi and 15. Forests maintain oxygen and carbon dioxide balance by absorbing carbon dioxide and releasing oxygen during photosynthesis. Hello hi and

 1. A bat emits ultrasonic sound of frequency 40,000 Hz. If wavelength is 0.0085 m, calculate the speed of sound used by the bat. 2. A person stands between two tall mountains and fires a starter pistol. They hear the first echo after 2 seconds and the second echo after 3 seconds. If the speed of sound is 340 m/s, what is the total distance between the two mountains? 3. In a longitudinal sound wave travelling through air, the distance between a compression and the nearest rarefaction is 0.85 m. The time period of the wave is 0.01 s. The amplitude of vibration is 4 mm. What is the speed of the sound wave?

 1. (c) Soil erosion: Removal of the fertile top layer of soil by wind, water, or human activities. (d) Deforestation: Large-scale cutting of forests by humans. 10. Decomposers are organisms that break down dead plants and animals. Examples: Bacteria and Fungi. They return nutrients to the soil and keep the forest clean. 14.Forests prevent floods by holding soil with roots, absorbing rainwater, and reducing fast water flow. 15. Forests maintain oxygen and carbon dioxide balance by absorbing carbon dioxide and releasing oxygen during photosynthesis.

91. Why spores are usually covered by a hard protective coat?  1. Why spores are usually covered by a hard protective coat? 2. What is meant by sexual reproduction? 3. What is meant by a unisexual flower? 4. What is meant by syngamy? 5. Define: (a) Speed (b) Time. 6. What is a simple pendulum? 7. When would we say an object is in motion? 8. The distance between two stations is 200 km. A train takes 4 hours to cover this distance. Calculate the speed of the train. 9. Show the shape of the distance–time graph for the motion in the following cases:    (a) A car moving with a constant speed.    (b) A car parked on a side road. 10. What is a circuit diagram? 11. What is heating effect of electric current? 12. What is magnetic effect of an electric current? 13. Give four applications of an electromagnet. 14. Draw the symbols to represent the following components of electrical circuits: Connecting wires, Switch in the ‘OFF’ position, Bulb, Cell, Switch in the ‘ON’ posi...

Two identical syringes are filled, one with water and the other with air, and then sealed at the nozzle. When equal force is applied to both pistons, the air-filled syringe compresses significantly, while the water-filled one barely moves. This observation is primarily used to prove: (A) Particles of gases have higher kinetic energy than liquids. (B) Intermolecular spaces in gases are much larger than in liquids. (C) Gases exert pressure equally in all directions. (D) Diffusion is faster in gases than in liquids.

45. Which gas is used by plant for respiration 46. In cataract which part is changed 47. Hardest part of human body 48. Only non metal that can conduct electricity 49. Which cell dont have nuckleus 50. Smallest cell of human 51. Biggest cell of human egg