26.The wavelength of X-rays is of the order of :

27.Three communicable diseases prevalent in developing countries caused by unsafe drinking water and bad sanitation are :

28.The phenomenon by which water molecules move from a water molecules move from a weaker solution to a stronger solution through a semi-permeable membrane is called :

29.Two cars, passing each other at high speed, are in danger of side swiping because :

30.Consider the following worms :1. Filaria worm 2. Guinea worm3. Hookworm4. PinwormWhich of the above worms are nematodes ?