Answer: B) -2 Explanation: The sum of the oxidation numbers in a compound must equal zero. In the compound hydrogen sulfide, H2S, the two hydrogen atoms have an oxidation number of +1, for a total of +2. Therefore, the oxidation number of sulfur in the compound is -2, and the sum of the oxidation numbers is 0.

Answer: C) Decomposers are those organisms that recycle matter in the ecosystem.. Explanation: Decomposers are organisms that break down dead or decaying organisms, and in doing so, they carry out the natural process of decomposition.   The statement "Decomposers are those organisms that recycle matter in the ecosystem" describes decomposers.

Answer: B) 2k1k2/k1+k2 Explanation: We know that,   The equivalent K =  L1 + L2L1K1+L2K2   where L1 & L2 are plate1 & Plate2 thicknesses, K1 & K2 are coefficient thermal conductivity of plate1 & Plate2 respectively.   But here L1 = L2 = L (say)   Then K = L+L/(L/K1 + L/K2)  =  2K1K2K1+K2

Answer: C) 246 Explanation: A Committee of 5 persons is to be formed from 6 gentlemen and 4 ladies by taking.    (i) 1 lady out of 4 and 4 gentlemen out of 6  (ii) 2 ladies out of 4 and 3 gentlemen out of 6  (iii) 3 ladies out of 4 and 2 gentlemen out of 6  (iv) 4 ladies out of 4 and 1 gentlemen out of 6    In case I the number of ways = C14×C46 = 4 x 15 = 60  In case II the number of ways = C24×C36 = 6 x 20 = 120  In case III the number of ways = C34×C26 = 4 x 15 = 60 In case IV the number of ways = C44×C16 = 1 x 6 = 6    Hence, the required number of ways = 60 + 120 + 60 + 6 = 246

Answer: B) 45 Explanation: Number of squares in the given figure is 16 + 9 + 19 + 1 = 45.

Answer: A) TRUE Explanation: Yes, the ability to do work is called Energy is True.

Answer: D) Kerala Explanation:

Answer: C) Hydrogen Explanation: Hydrogen is the common element to all Acids. But every element which contains Hydrogen is not an Acid. Most of the acids also contain Oxygen.