Observe the diagram and answer the following:
$(a)$ Which group of plants exhibit these two types of cells?
$(b)$ What is the first product of the $C_4$ cycle?
$(c)$ Which enzymes are present in bundle sheath cells and mesophyll cells?

(N/A) Plants that exhibit these two types of cells (mesophyll and bundle sheath) are known as $C_4$ plants. Examples include plants from the Poaceae family,such as sugarcane and maize.
$(b)$ The first stable product of the $C_4$ cycle is a $4$-carbon compound called Oxaloacetic Acid $(OAA)$.
$(c)$ In mesophyll cells,the enzyme $PEP$ carboxylase $(PEPCase)$ is present,which fixes atmospheric $CO_2$ into $OAA$. In bundle sheath cells,the enzyme $RuBisCO$ (Ribulose$-1,5-$bisphosphate carboxylase-oxygenase) is present,which performs the Calvin cycle to fix $CO_2$ into $3$-carbon $PGA$ (Phosphoglyceric acid).