What does this Rebus Picture mean?

Be active and find the killer in the picture Riddle below.

Take one out and scratch my head, I am now black but once was red. What am I?

Sally lives in a place where six months of the year is mild summer and the temperature drops significantly the other six months. She owns a lake where there is a small island. She wants to build a house on the island and needs to get materials there. She doesn’t have a boat, plane, or anything to transport them to the island. How does Sally solve this problem?

What's the only room from which no one can enter or leave

You have to fill the below given grid in a manner that every row and column contains the digits 1 to 6. Also, make sure that the squares that are connected with each other must contains the same digit.

What does it mean?

Prove that the below maths equation is true.

8 + 8 = 91

A man is looking at a photograph of someone. His friend asks who it is. The man replies, “Brothers and sisters, I have none. But that man’s father is my father’s son.” Who was in the photograph?

Can you find out the remainder when 3^300 is divided by 5?