It's opt (3) Pisum sativum ..bcoz...it's a C3 plant in which the carboxylation occurs only once ..while the others are C4 plants ..in which the carboxylation occurs twice (both in mesophyll and bundle sheath cells)

Odd One out (w.r.t double carboxylation):

Explanation:
To determine the odd one out among Zea Mays, Sugarcane, Pisum sativum, and Sorghum in terms of double carboxylation, we need to understand what double carboxylation means and how it relates to these plants.

Double carboxylation:
Double carboxylation refers to the process of fixing carbon dioxide (CO2) twice during photosynthesis. It occurs in certain plants called C4 plants, which have specialized leaf anatomy and biochemical pathways to optimize photosynthesis in hot and arid conditions.

C4 plants:
C4 plants have a unique carbon fixation pathway that allows them to efficiently capture and concentrate CO2 in specialized cells called bundle sheath cells. This pathway involves two distinct types of cells: mesophyll cells and bundle sheath cells.

Mesophyll cells:
Mesophyll cells are located in the outer layer of the leaf and are responsible for the initial fixation of CO2 into a four-carbon compound called oxaloacetate. This fixation is catalyzed by an enzyme called phosphoenolpyruvate carboxylase (PEP carboxylase).

Bundle sheath cells:
Bundle sheath cells are located deeper within the leaf and surround the vascular bundles. They contain a high concentration of chloroplasts and are responsible for the second fixation of CO2 into sugars. This fixation is catalyzed by the enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco).

Analysis of the given plants:
1. Zea Mays (Maize): Zea Mays is a C4 plant. It has specialized leaf anatomy and performs double carboxylation, fixing CO2 twice during photosynthesis.
2. Sugarcane: Sugarcane is also a C4 plant. Similar to Zea Mays, it has specialized leaf anatomy and performs double carboxylation.
3. Pisum sativum (Pea): Pisum sativum is not a C4 plant. It follows the C3 carbon fixation pathway, in which CO2 is fixed once during photosynthesis. Therefore, it does not perform double carboxylation.
4. Sorghum: Sorghum is a C4 plant. It has specialized leaf anatomy and performs double carboxylation, fixing CO2 twice during photosynthesis.

Conclusion:
Among the given plants, Pisum sativum (Pea) is the odd one out in terms of double carboxylation. Unlike Zea Mays, Sugarcane, and Sorghum, Pisum sativum follows the C3 carbon fixation pathway and does not perform double carboxylation.