[QUOTE=ghulammujtaba86;273951]Echo is direct reflection of sound
http://en.wikipedia.org/wiki/Echo_(phenomenon)
Some more wrong answers
e) None of these
alkali are elements of first group Na K etc
wrong answer: The correct answer is slaked lime. Its basically a compound of Calcium. The rest of the explanation is in your answer
its used by farmers mostly
42) Digestion is wrong. Metabolism is the correct answer. Without metabolism the cells cannot obtain energy to survive/live. so without metabolism you are not a living creature.