The radio-labelled carbon in carbon dioxide supplied to potato plants in an experiment was eventually seen in the tuber. Trace the movement of the labelled carbon dioxide.

(N/A) $1$. During photosynthesis,the potato plant takes up the radio-labelled $CO_2$ $(^{14}CO_2)$.
$2$. This carbon is fixed into organic compounds,primarily glucose $(C_6H_{12}O_6)$,through the Calvin cycle.
$3$. The glucose is then converted into sucrose $(C_{12}H_{22}O_{11})$,which is the primary form of sugar transported in plants.
$4$. This radio-labelled sucrose is translocated from the leaves (source) to the tubers (sink) through the phloem tissue via sieve tube elements.
$5$. The presence of the radio-labelled carbon in the tuber can be detected using the autoradiography technique.