What is incorrect regarding apoplast transport in plants?
1. The apoplast is formed by the continuum of cell walls of adjacent cells as well as the extracellular spaces.
2. Transport velocity is lower in the apoplast than in the symplast.
3. Apoplast transport also accounts for a higher proportion of water transport in plant tissues than does symplastic transport.
4. The apoplastic pathway is also involved in passive exclusion.

The apoplast pathway in plants includes all the following except:
1. the lumen of a xylem vessel
2. the lumen of a sieve tube
3. the lumen of tracheids
4. the cell wall of a root hair

The Casparian strip in plant roots:
1. is located in the walls of the outermost portion of the cortex.
2. is composed predominantly of lignin and hence is impermeable to water.
3. ensures active uptake of all minerals by the roots.
4. ensures that all water and dissolved substances must pass through a cell membrane before entering the vascular cylinder.

Substances travelling via the symplast move from cell-to-cell through:
1. membrane proteins.
2. phospholipid channels.
3. tonoplast.
4. plasmodesmata.

Unloading of mineral ions occurs at the fine vein endings through:
1. diffusion and, are passively taken up by the sink cells
2. active transport and, are passively taken up by the sink cells
3. diffusion and, are actively taken up by the sink cells
4. active transport and, are actively taken up by the sink cells