What does the below image rebus riddle means ?

There is something which is always coming but never arrives?

In a science lab, a petri dish hosts a healthy colony of yeast for an experiment. Now every minute, all the yeast cells divide into two. At noon, there was just a single cell of yeast and at 1:22, the Petri dish was half full. Can you calculate when the dish will be full of yeast?

What has many keys but can’t open a single lock?

Use only one mathematical symbol and all numbers (0-9) to get a sum of 99

You need to arrange three 7 and mathematical symbols to form number 1?

At my favorite fruit stand,
an orange costs 18,
a pineapple costs 27,
and a grape costs 15.
Using the same logic, can you tell how much a mango costs?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

What jumps when it walks and sits when it stands?

John named his first son Alpha, second Beta, third Charlie and fourth Delta. What is the fifth son's name?