How can you make number one disappear by adding something to it?

I have nine bottles of wine and one of the nine bottles is poisoned.
I need to find the poisoned bottle with two facts
(1) Poison is deadly, only a sip will cost death
(2) I have two mice to do so.

How should I do it?

I live in a bowl. I can swim. I have a tail. I also have fins and big eyes. What am I?

All of Jacob's shoes are red except two.
All of Jacob's shoes are green except two.
All of Jacob's shoes are yellow except two.

How many shoes does Jacob have?

There is a shop where written:
Buy 1 for $1
10 for $2
100 for $3
I needed 999 and still only paid $3. How could this be financially viable for the shop-keeper?

It has a long neck, A name of a bird, Feeds on cargo of ships, It's not alive,

What is it?

Solve the counting riddle by identifying the number of triangles in the given picture.

There was an aeroplane crash, every single person died, but two people survived. How is this possible?

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

What number does the below three word/phrase identify and why?
1. Deck
2. Year
3. Singing in the Rain