What does this below rebus puzzle mean?

In the given picture, you can find two letters missing. When two particular letters are placed in the missing spots, you get an eight-letter word while reading in the anti-clockwise direction. Can you find out the missing letters and the missing word eventually?

A cricket has 6 legs, a squirrel has 4 legs and a spider has 8 legs.

In a local zoo, it was found that the total number of legs is 612. Also, there are equal number of each of the above animals/insects.

Can you find out how many animals are there in the zoo?

What does below chemistry rebus means?

Identify the hidden meaning behind this picture?

If in a car race, the man who came two places in front of the last man finished one ahead of the man who came fifth, how many contestants were there?

In 1990, a person is 15 years old. In 1995, that same person is 10 years old. How can this be?

Can you find a rabbit in the given picture?

If you're 8 feet away from a door and with each move you advance half the distance to the door. How many moves will it take to reach the door?

A famous swimmer can swim downstream in a lake in exactly 40 minutes with the lake current.
He can swim upstream in that lake in exactly 60 minutes against the lake current.
The length of the lake is 2 km.

How long he can cover the distance of one side at a still lake with no current?