What does below chemistry rebus means?

Find The Odd One Out

1. FLOW
2. SNIP
3. TRAP
4. DRAW
5. BACK

A word I know,
Six letters contain,
Subtract just one,
And twelve is what remains.

In the below-given picture of a pretty girl, there is something wrong. Can you find out what it is?

Here is what you have to do. You have to throw a ball as hard as you can but it must return back to you even if it does not bounce at anything. Also, you have nothing attached to the ball. There is no one on the other end to catch that ball and throw it back at you.

How will you do it?

Who can jump higher than a Mountain?

Can you find the missing letter in the sequence?
S - T - I - L - ? - T - F - Y - C

A sundial has the fewest moving parts of any timepiece. Which has the most?

A pond had 60 fish, out of which, all but 20 died.
How many fishes are now present in that pond?

A research team went to a village somewhere between the jungles of Africa. Luckily for them, they reached the day when quite an interesting custom was to be performed. The custom was performed once a year as they confirmed and was performed in order to collect the taxes from every male of the region.

The taxes were to be paid in the form of grains. Everyone must pay pounds of grain equaling his respective age. This means a 20-year-old will have to pay 20 pounds of grain and a 30-year-old will pay 30 pounds of grain and so on.

The chief who collects the tax has 7 weights and a large 2-pan scale to weigh. But there is another custom that the chief can weigh only three of the seven weights.

Can you find out the weights of the seven weights? Also, what is the maximum age of the man that can be weighed for the payment of taxes?