What has 13 hearts but no other organs?

I was born in a small house and I live in it all alone. No windows and no doors have been assigned to my house. The only way I can go out is by breaking through the walls of my house.

Who am I?

On a certain island, people are gifted with assorted eye colours. There are a hundred green-coloured and a hundred grey-coloured pairs of eyes. On that island, there is no mirror available. Thus no one knows the eye color of their own. They could have asked each other but that is prohibited. They are not allowed to converse with each other. However, they can study and analyze other's eyes. They don't even know the statistics so it is believable to them that their eyes can be blue as well. There is a chance of freedom from the island. If anyone can guess the colour of his own eyes correctly, he will be set free and can leave the island.

On one particular day, an outsider comes to the island and announces that he has seen someone with grey colour eyes. What will happen now?

If we add four times the age of John four years from now to five times his age five years from now we get ten times his current age.

How old will John be two years from now?

I am a type of food that is often found in the fridge and can be white in colour. What I am?
Hint 1: I am a dairy product.
Hint 2: You can spread me on the bread.

John named his first son Alpha, second Beta, third Charlie and fourth Delta. What is the fifth son's name?

A man stands on one side of a river, his dog on the other. The man calls his dog, who immediately crosses the river without getting wet and without using a bridge or a boat. How did the dog do it?

A red house is made out of red bricks. A yellow house is made out of yellow bricks. And, a blue house is made out of blue bricks. So, what is a greenhouse made of?

Identify the 10 differences between the two given pictures.

If,

A + B = C
D - C = A
E - B = C

Based on the above equations, find out the answer for:

D + F = ?