How do you distinguish between a lever of the first order from second or a third order lever?

State the class of lever to which scissors belong giving the relative positions of Load$\left(L\right)$, Effort$\left(E\right)$ and Fulcrum$\left(F\right)$.

State the class of lever to which sugar tongs belong giving the relative positions of Load$\left(L\right)$, Effort$\left(E\right)$ and Fulcrum$\left(F\right)$.

State the class of lever to which nutcracker belong giving the relative positions of Load$\left(L\right)$, Effort$\left(E\right)$ and Fulcrum$\left(F\right)$.

Figure given below gives an arrangement of moving and fixed pulleys. Copy the diagram and show the direction and magnitude of forces exerted by the four strings marked $1$ to $4$. What is the load that can be lifted by the effort $E$? Calculate the mechanical advantage of this system.