Checkpoint $3\mathrm{.}4$

$1.$Given AB $->$ CDE, is R$($A$,$ B$,$ C$,$ D$,$ E$)$ in $2$NF$?$

$2.$Given B $->$ ACDE, is R$($A$,$ B$,$ C$,$ D$,$ E$)$ in $2$NF$?$

$3.$Given AB $->$ CD and B $->$ E$,$ is R$($A$,$ B$,$ C$,$ D$,$ E$)$ in $2$NF$?$

$4.$If a table is in the $1$NF and you have no concatenated key, you do not have to worry about $2$NF problems $($True$/$False$)?$