40) The output of a diesel engine can be increased without increasing the engine revolution or size in following way

41) Taj Mahal is threatened due to the effect of

42) Which of the following countries doesn't have common border with India?

43) 'A' sold a motor cycle to 'B' at a gain of 15%, 'B' sold it to 'C' at a gain of 20%. If 'C' paid Rs. 897, then 'A' would have paid

44) Neutrons are present in all atoms except