Answer: A) listening to a cricket chirp at night and counting the number of chirps per minute Explanation:

Answer: A) Stratification Explanation: Stratification as actually the settling down of sediments with different properties to form layers/strata over years. Stratification especially occurs on the bed of water bodies such as oceans.   Stratified sedimentary rocks are used to study the ecological conditions over previous years/eras.     The other choices like Windstorms, Glacial Ice and Stream water are mediums which sediments are transported.

Answer: B) 40 Explanation: The third proportional of two numbers p and q is defined to be that number r such that p : q = q : r.   Here, required third proportional of 10 & 20, and let it be 'a' => 10 : 20 = 20 : a 10a = 20 x 20 => a = 40   Hence, third proportional of 10 & 20 is 40.

Answer: D) Trajectory Explanation: The path traced by planet is called Orbit. Similarly, the path traced by projectile is called Trajectory.   Hence, Planet : Orbit : : Projectile : Trajectory.

Answer: C) does not use oxygen but tolerates it. Explanation:

Answer: A) Vitamins B & C Explanation: Vitamins are essential nutrients found in foods. They perform specific and vital functions in a variety of body systems, and are crucial for maintaining optimal health.   The two different types of vitamins are fat-soluble vitamins and water-soluble vitamins.   Fat-soluble vitamins :  Vitamins A, D, E and K — dissolve in fat before they are absorbed in the bloodstream to carry out their functions. Excesses of these vitamins are stored in the liver, and are not needed every day in the diet.   Water-soluble vitamins : Vitamins dissolve in water and are not stored by the body. Since they are eliminated in urine, we require a continuous daily supply in our diet. The water-soluble vitamins include the vitamin B-complex group and vitamin C.   Water-soluble vitamins are easily destroyed or washed out during food storage or preparation.

Answer: C) Future Explanation: Yes, future is always infront of us, but no one can see it.

Answer: A) doing more work in less time. Explanation: Doing more work in less time, results in an increase in power to do a work.