Which of the following is correctly

Which of the following isotope of uranium is used as a nuclear-fuel in reactors?

Which vitamin can be synthesized in the liver?

How many moles of carbon dioxide are present in a gas jar containing 1.501 × 10²² molecules of CO₂?

Match List-I with List-II and select the correct answer using the code given below the Lists:

Which of the following can be beaten into thin sheets?

Which of the following transitions in hydrogen atom will result in emission of radiation of longest wavelength?

Which of the following constitutes a food chain ?

Among petroleum refinery products, which has the lowest boiling point?

The centre of gravity of a sprinter during the race lies –