/7 Science Quiz (for 12 to 16 years old): Quiz 2 1 / 7The hardest substance available on earth is Iron Diamond Gold Platinum 2 / 7Bromine is a black solid red liquid colourless gas highly inflammable gas 3 / 7Quartz crystals normally used in quartz clocks etc. is chemically sodium silicate a mixture of germanium oxide and silicon dioxide germanium oxide silicon dioxide 4 / 7The gas usually filled in the electric bulb is carbon dioxide Nitrogen hydrogen oxygen 5 / 7Washing soda is the common name for Calcium bicarbonate Sodium bicarbonate Sodium carbonate Calcium carbonate 6 / 7Which of the gas is not known as green house gas? Methane Nitrous oxide Carbon dioxide Hydrogen 7 / 7What is the primary cause of climate change? Animal activity Natural factors Human activity Climate change is primarily caused by human activity, particularly the burning of fossil fuels and deforestation.Your score is 0% Restart quiz Next quiz Please rate the quiz Send feedback By WordPress Quiz plugin