what does this picture(rebus) riddle means ?

What is wrong in the below Picture?

A man calls his dog from the opposite side of a river. The dog crosses the river without a bridge or a boat and manages to not get wet. How is this possible?

I am not a bull but I have horns.
I am not an ass but I have a pack saddle.
Wherever I go, I leave silver behind me.

Who am I?

Which is faster, Heat or Cold ? Explain.

How many minutes are there in Feb 2017?

Note: The shortest answer is the correct answer.

Can you find out which options fits best with the missing column?

How many words can a pen with half refill write?

Can you find out the smallest number that can be conveyed as the sum of three squares in three unique ways?

There is a square piece of paper with a hole that is denoted by the circle on the top right side in the given picture. You have to cut the paper in a manner that it forms two and only two separate pieces of paper and then rearrange the pieces in a manner that the holes come in the centre of the paper.