What does this below rebus puzzle mean?

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

Complete the following series. It.s very logical:

1, 4, 5, 6, 7, 9, 11, __?

What's the next in the series?

H, Be, F, S, Mn, Kr, In, Gd, Tl, ?

By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?

Find the combined weight of the Cat, Dog and Rabbit in the given picture.

Count The number of F's in the paragraph below:

"FINISHED FILES ARE THE RESULT OF YEARS OF SCIENTIFIC STUDY COMBINED WITH THE EXPERIENCE OF YEARS"

There are three boxes of different sizes with three cupcakes inside each of the boxes in Christina's kitchen. At night her daughter wakes up and goes to the kitchen. She opens a box and eats all three cakes.

But in the morning Christina finds out that each box still had three cupcakes. How?

Why are all black people so quick ?

Replace each alphabet with the number (1-9) to make the below equation correct.

AB * C = DE - F = GH / I