What does the below rebus riddle means?

Why do people go to bed?

I possess a head

I flaunt a tail

But I don't have mouth or legs

Can you find out who I am?

I never stop running even when I standstill. If I am formed by joining two identical bodies together, can you guess who I am?

Can you divide numbers from 1 to 9 (1 2 3 4 5 6 7 8 9) into two groups so that the sum of the numbers of each group is equal?

Note: 9 cannot be turned over to make it 6.

I can write cow in 13 letters.

Can You?

There are two dice with empty faces in front of you and a marker. You can mark any number on each of the faces of the two dice, but you have to display all 31 days of the month using the two of them.

Which numbers will you mark on which dice so that you can easily depict all the dates of the month?

Two guards were on duty outside a barracks. One faced up the road to watch for anyone approaching from the North. The other looked down the road to see if anyone approached from the South. Suddenly one of them said to the other, "Why are you smiling?"

How did he know his companion was smiling?

It is raining today at 11:59 am. What is the probability of sunny weather after 72 hours?

You can see it everyday, But cannot touch it at will. What is it?