Select the correct option:
$(1)$ $C_4$ plants have double the efficiency of carbon fixation compared to $C_3$ plants.
$(2)$ Sugar is transported from source to sink through the $\text{phloem}$ / $\text{xylem}$ tissue.

Analogy type questions:
$(1)$ Middle lamella : Calcium pectate :: Cytochrome : ........
$(2)$ Thiamine : Vitamin :: Manganese : ........

'Sun basket' is

Which of the following statements is correct regarding $C_4$ plants?

Find the incorrect statement$(s)$ about photosynthesis from the following:
$A$. The water-splitting complex is associated with $PS-I$.
$B$. $C_4$ plants use the $C_3$ pathway of $CO_2$ fixation as the main biosynthetic pathway.
$C$. In $C_4$ plants, photorespiration does not occur.
$D$. $C_3$ plants exhibit 'Kranz' anatomy.
$E$. $ATP$ synthesis in chloroplast occurs through chemiosmosis.

Explain the information about the discovery of $C_3$ and $C_4$ pathways.