What runs around the whole yard without moving?

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?

There is a brick of gold and a brick of iron in a boat (both 10-inch blocks), if they are both dropped into the water which will make the water level higher?

Cristina leaves home and then she makes exactly 3 left turns and returns home where she found 2 girls wearing the mask.

Who are these two masked girls?

Its something that each of us devours,
Not just us but birds, beats, trees, and flowers,
Frets iron and nibbles steel,
Toil hard stones to meal,
Exterminates king, collapse town,
And blows the mountains down.

Can you place three balls such that the equation shown in the picture holds true?

Christina, Allison and Lena are 3 daughters of John a well-known Mathematician, When I asked John the age of their daughters. He replied "The current age of her daughters is prime. Also, the difference between their ages is also prime."

How old are the daughters?

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

What do you call a fish without an eye?

The cream is heavier than Milk. True or False?