To investigate how substances are transported to supply cells throughout a vascular plant, a researcher feeds carbon-14 dioxide ( $14CO2^{14}\text{CO}_2$ ) to a mature leaf midway up the stem, and adds water labeled with tritium ( $3H^3\text{H}$ ) to the soil.

Which of the following correctly describes the vascular tissue pathway and the direction of transport for each labeled substance?

$14C^{14}\text{C}$ -solutes move bidirectionally (upwards and downwards) in the phloem; $3H^3\text{H}$ -water moves unidirectionally (upwards only) in the xylem.

$14C^{14}\text{C}$ -solutes move unidirectionally (downwards only) in the phloem; $3H^3\text{H}$ -water moves bidirectionally in the xylem.

$14C^{14}\text{C}$ -solutes move bidirectionally in the xylem; $3H^3\text{H}$ -water moves unidirectionally (upwards only) in the phloem.

$14C^{14}\text{C}$ -solutes move unidirectionally (upwards only) in the phloem; $3H^3\text{H}$ -water moves bidirectionally in the xylem.

Which of the following correctly describes the vascular tissue pathway and the direction of transport for each labeled substance?

$14C^{14}\text{C}$ -solutes move bidirectionally (upwards and downwards) in the phloem; $3H^3\text{H}$ -water moves unidirectionally (upwards only) in the xylem.

$14C^{14}\text{C}$ -solutes move unidirectionally (downwards only) in the phloem; $3H^3\text{H}$ -water moves bidirectionally in the xylem.

$14C^{14}\text{C}$ -solutes move bidirectionally in the xylem; $3H^3\text{H}$ -water moves unidirectionally (upwards only) in the phloem.

$14C^{14}\text{C}$ -solutes move unidirectionally (upwards only) in the phloem; $3H^3\text{H}$ -water moves bidirectionally in the xylem.

2.1 Supplying the cell

Question 5

Markscheme

2.1 Supplying the cell

Question 5

Markscheme

2.1 Supplying the cell

Question 5

2.1 Supplying the cell Questions

2.1 Supplying the cell

Question 5

2.1 Supplying the cell Questions