I dont understand these questions please help

Plz determine whether the polynomial is a difference of squares and if it is, factor it. y2 – 196 is a difference of squares: (y + 14)2 is a difference of squares: (y – 14)2 is a difference of squares: (y + 14)(y – 14) is not a difference of squares

What is the circumference of a circle with an area of 50.24 cm²?

The diameter of a bacteria colony that doubles every hour is represented by the graph below. what is the diameter of the bacteria after 8 hours? graph of a curve passing through the points zero comma 1, one comma two, two comma four, and three comma eight