In ${\mathrm{C}}_4$ plants, why is ${\mathrm{C}}_3$ pathway operated in bundle sheath cells only?

What would have happened if ${\mathrm{C}}_4$  plants did not have Kranz anatomy?

Why does RuBisCO carry out preferentially carboxylation than oxygenation in C4 plants?

How can you identify whether the plant is $C_3$ or $C_4$? Explain or Justify.

In ${\mathrm{C}}_4$ plants, bundle sheath cells carrying out Calvin cycle are very few. Even though, ${\mathrm{C}}_4$  plants are highly productive. Explain.

What is functional significance of Kranz anatomy?