What is the approximate percentage of carbon in the Earth's crust ?

In the ordinary fire extinguisher, Carbon dioxide is generated by the reaction of

Which of the following is not in the form of crystal?

Which one of the following sets of elements was primarily responsible for the origin of life on the Earth?

Which one of the following statements is NOT correct ?

What is the law in which under the same conditions of temperature and pressure, equal volumes of all gases contain equal number of molecules?