Answer: C) Both A & B Explanation: The term biodiversity refers to the variety of life on Earth at all its levels, from genes to ecosystems, and the ecological and evolutionary processes that sustain it.

Answer: A) 80% Explanation: Water in 60 gm mixture=60 x 75/100 = 45 gm. and Milk = 15 gm.   After adding 15 gm. of water in mixture, total water = 45 + 15 = 60 gm and weight of a mixture = 60 + 15 = 75 gm.   So % of water = 100 x 60/75 = 80%.

Answer: D) His son Explanation: Since Akhil has no brother or sister, so he is his father's only son.So wife of Akhil's father's son---Akhil's wife.Thus, Akhil's wife is the man's mother or the man is Akhil's son.

Answer: D) 8:3 Explanation: Let the man's rate upstream be x kmph and that downstream be y kmph. Then, distance covered upstream in 8 hrs 48 min = Distance covered downstream in 4 hrs. x x 8 4 = (y x 4) 5 44 x =4y 5  y = 11 x. 5  Required ratio = y + x : y - x 2 2    = 16x x 1 : 6x x 1 5 2 5 2    = 8 : 3 5 5    = 8 : 3.

Answer: B) 2 Explanation: Given that x = 2+ 223 + 213   So x - 2 = 223 + 213   Now cubing on both sides, we get     => x3-8-6x2+12x = 4 + 2 + 6(x-2)   Therefore, x3-6x2+6x = -6 + 8 = 2

Answer: C) 123 Explanation: We know that, M1 × D1W1 = M2 × D2W2 Here M1 = 1, D1 = 6 min, W1 = 1 and M2 = M, D2 = 90 min, W2 = 1845   1 × 61 = M × 901845  => M = 123

Answer: B) CF4 Explanation: You have to consider three things. 1. First, are the bonds polar? Look at differences in electronegativity and if  it is >0.5, bonds are polar.   2. Second, does the molecule have unshared electron pairs? If so, they generally lead to a polar molecule.   3. Third, is the molecule symmetric? If so, then although the bonds may be polar, the symmetry cancels out the individual bond polarity and the molecule is non polar. CF4 follows all the rules above and has a symmetric distribution of charge, making it nonpolar. The others all have asymmetric charge distributions.   Hence, CF4 represents a Non-polar molecule.

Answer: B) -2 Explanation: We know that in A.P series18th term = a + 17d29th term = a + 28dBut given a + 17d = 29..........(i)a + 28d = 18......... (ii)Solving equation (i) and (ii), we getd = -1put d = -1 in any of the above equations and we get, a = 46Now, we know 49th term can be written as, a + 48d putting the value of a and d in the above equation,a + 48d = 46 + 48(-1) = 46 - 48 = -2 Hence, the 49th term is -2.