What month of the year has 28 days?

Whats the next number in the below number sequence pattern.

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

It is a six-letter word.
The first four letters are me.
The second and last letters are the same.
The fourth second and last letter is payment.

Who is it?

A donkey is behind another donkey
I'm behind that second donkey
But there is a whole nation behind me

It is a murder you can describe in a word.

How many cubic feet of dirt are in a hole of one foot deep, three feet long, and two feet wide?

What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?

There is a hypothetical state between the USA and Mexico border 'Tango'.
Here 70 percent of the population have defective eyesight, 75 percent are hard of hearing, 80 percent have Nose trouble and 85 percent suffer from allergies, what percentage (at a minimum) suffer from all four ailments?

What can go up a chimney down, but can’t go down a chimney up?

What has 13 hearts but no other organs?