What has a ring but no finger?

Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?

Count the number of balls in picture below:

Find out a multi-digit number that if multiplied by the number 9 or any of its multiplications products (i.e. 18, 27, 36, 45,..) will result in the multiplication factor repeated (n) number of times.

What can run but never walks, has a mouth but never talks, has a head but never weeps, has a bed but never sleeps?

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?

An evil man kidnapped someone and made them take one of two pills. One was harmless, but the other was poisonous. Whichever pill the victim took, the kidnapper took the other one. The victim took their pill with water and died. The kidnapper survived. How did the kidnapper get the harmless pill?

Spot 5 differences in two Christmas tree below:

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?

Andrew sees a very rare bird named "Ruppell's vulture". Soon Andrew was dead. Can you explain the mystery, Mr. Sherlock?