The hardest substance available on earth is

A. Platinum

B. Quartz

C. gold

D. Diamond

Please do not use chat terms. Example: avoid using "grt" instead of "great".

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  1. Lightening cause rainfall because
  2. Earth's seasons are caused by which of the following?
  3. Cell membrane is
  4. The fastest acting enzyme in the biological kingdom is
  5. Which of the following parts of the sun is easily visible only during a total solar eclipse?
  6. Old-written material, which cannot be read easily can be read by
  7. The property of a substance to absorb moisture from the air on exposure is called
  8. Brass gets discoloured in air due to the presence of which gas in air
  9. Epoxy resins is used as
  10. The marine animal called dugong which is vulnerable to extinction is a/an
  11. One fathom is equal to
  12. The accumulation of stress along the boundaries of lithospheric plates results in which of the following?
  13. The removal of top soil by water or wind is called
  14. Which of the following items will be attracted to the north pole of a permanent magnet by a magnet force?
  15. Which of the following elements is obtained from sea weeds ?
  16. The formula of Plaster of Paris is
  17. The major ingredient of leather is
  18. Permanent hardness of water can be removed by adding
  19. What is the unit for measuring the pitch or frequency of sound ?
  20. The metal used in storage batteries
  21. The oxide of Nitrogen used in medicine as anaesthetic is
  22. Which of the following is most likely to cause a rise in the average temperature of earth's atmosphere…
  23. The metallic constituents of hard water are
  24. The type of glass used in making prisms and lenses is
  25. The metal that is present in Photo Films is
  26. The hardest substance available on earth is
  27. The recent atomic weight scale is based on
  28. Bromine is
  29. The smallest functional and structural unit of kidney is called as
  30. Glass is made from the mixture of