Who invented vacuum tubes?

What is backup?

The ability to easily add addi-tional users means that a net work is

राष्ट्रिय जनगणना २०७८ को नारा के हो?

Which of the following is valid statement?

कामिरिता शेर्पाले २८ औँ पटक सगरमाथा आरोहण कहिले गरे?

Material consisting of text and numbers is best presented as

"Zipping" a file means

When did John Napier develop logarithm?