It is because they do not have Navels.

The answer is 16
Logic,
4-1=3
9-4=5
?-9=x
25-?=y
36-25=11
49-36=13
64-49=15
81-64=17
So in each case the difference is 2. So  in place of x i will be 7(5+2) and in place of y it will be 9 (7+2)
Hence
?-9=7
=> ?=16

The answer is 7103: 1

Logic applied is that i have added all the numbers on Left Hand Side.
(i)If the sum is an odd number then the digit at the Unit’s place will be the answer.
8+4+3+2 =17 so the answer is 7
9+0+6+4 =19 so the answer is 9
(ii) If the sum is divisible by 2 then add 2 to the answer.
5+1+4+4 =14 so the answer is 14+2=16
(iii) If the sum is divisible by 5 then the answer will be zero
9+2+1+3 = 15 so the answer is 0

Now, 7+1+0+3 = 11 so the answer will be 1

I choose to pick 10
You can pick any number you wish between 12 and 5 and this has nothing to do with the previous addition drill.
Most people will pick 7 because 12-5=7 correct ? But the fact is that this answer will come due the influence from the previous addition drill.
So finally you are just asked to pick any random number and it has got nothing to do with the additions.

I would use a Magnifying glass and focus the bright sun light on the string through the glass so that i can make a fire and detach the ring from the string and thus making it to drop the ring inside the bottle.

The answer will be 39

Explanation:
3*2 – 1 = 5
5*2 – 2 = 8
8*2 – 3 = 13
13*2 – 4 = 22
22*2 – 5 = 39

One more logic is that if you observe closely you can see that
1 no lies in between 3 and 5 (i.e the no is 4)
2 nos lie between 5 and 8 (i.e 6 and 7)
similarly 4 nos between 8 and 13
8 nos between 13 and 22
and in each case the number is getting doubled. So 16 nos will be there between 22 and the next number and thus the number will be 39