$5.$ In a three$-$phase flow, the presence of solids can:

A$)$ Decrease the overall pressure drop

B$)$ Increase the gas holdup

C$)$ Stabilize the flow regime

D$)$ All of the above

$6.$ The dynamics of gas$-$solid$-$liquid contactors are crucial for:

A$)$ Decreasing the reaction time

B$)$ Maximizing energy consumption

C$)$ Enhancing mass and heat transfer

D$)$ Reducing material strength

$7.$ A packed bed reactor is used primarily for:

A$)$ Phase separation

B$)$ Heat exchange

C$)$ Catalytic reactions

D$)$ Filtration

$8.$ Fluidized beds are advantageous due to:

A$)$ Low pressure drop

B$)$ High mass and heat transfer rates

C$)$ Simple construction

D$)$ High energy efficiency only