$18$ a$)$ Explain with example $2$NF$,3NF$ and BCNF$.$

$8$

b$)$ Consider a relation schema Y Z W P $)($above table $R)$ is decomposed into R$1(x$ Y $6Z)$ and R$2($ Z W P$).$ Determine whether the above R$1$ and R$2$ are Lossless or Lossy?