What goes up but never comes down?

Be active and find the killer in the picture Riddle below.

What number comes next in the series?

5 15 5 18 5 24 14 20 _

In a boat, the father of a sailor's son is sitting with the son of the sailor. However, the sailor is not present on the boat.

Can this even be possible?

Can you place six matchsticks in a manner that each of the matchsticks is in touch with the other five matchsticks?

In a basket of apples,
when counted in twos, there was one extra
when counted in threes, there were two extra when counted in fours, there were three extra
when counted in fives, there were four extra
when counted in sixes, there was five extra.

However, if the apples were counted in sevens, no extra apple was left. Can you calculate the minimum number of apples that were present in the basket?

You see me once in June, twice in November, and not at all in May. What am I?

What seven-letter word has hundreds of letters in it?

What is black when you buy it, red when you use it, and gray when you throw it away?

I am a five-letter word under you,
Remove the first letter and I am above you,
Remove the second as well and I am around you.

Who am I?