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 59

Markscheme

2.1 Supplying the cell

Question 59

Markscheme

2.1 Supplying the cell

Question 59

2.1 Supplying the cell Questions

2.1 Supplying the cell

Question 59

2.1 Supplying the cell Questions