AP BIOLOGY

Detailed explanation-1: -Phloem transport is bidirectional because sucrose gets accumulated in the phloem tissue and absorbs water creating a high turgor pressure. Other areas have low turgor pressure due to loss of water.

Detailed explanation-2: -Phloem is bidirectional in terms of transportation, meaning the flow of food is in both the directions. There are two main reasons due to which the xylem is unidirectional, namely positive root pressure and transpiration pull.

Detailed explanation-3: -Note that the fluid in a single sieve tube element can only flow in a single direction at a time, but fluid in adjacent sieve tube elements can move in different directions.

Detailed explanation-4: -Phloem tubes can carry sugars and amino acids in a variety of directions; depending on where the source and the sinks are located (sometimes roots can be sources or sinks).

Detailed explanation-5: -The movement of fluid in the phloem, a process called translocation, can occur in any direction, up or down the plant. However, the fluid typically flows from source cells to sink cells.