If you say my name, I will no longer exist. What am I?

John was going on a jungle trip. He asked his wife to pack something to eat, something to drink and something to burn if he feels cold in the jungle. When John opens the backpack he found just one thing in the bag. What was it?

Why 1729 is a magic number? Answer Logically.

I came first on earth but second on the heaven.
I also came twice in a week but found just once in a year.
I stay away from months but you can find me in February.

What am I?

I look flat, but I am deep. Hidden realms I shelter. Lives I take, but the food I offer. At times I am beautiful. I can be calm, angry, and turbulent. I have no heart but offer pleasure as well as death. No man can own me, yet I encompass what all men must have. What am I?

What month of the year has 28 days?

What has one letter and starts with an E?

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?

Before Mount Everest was discovered, what was the highest mountain in the world?

What have one eye but still cannot see?