In the ratio 08:27 :: ?:64, what number completes the pattern?

Which of the following is a 'Tadbhav' (evolved/derived) Hindi word?

Choose the correct article for the blank: 'The battalion had to march through ____ hot sand of the desert.'

With the help of which organ does an Amoeba swallow its food?

What is the unit for measuring the purity of gold?