The Existence of a Hydrostatic Pressure Gradient in Phloem Tubes

question 33

Multiple Choice

The existence of a hydrostatic pressure gradient in phloem tubes can be accounted for by

• A)the fact that the leaves are higher than the roots, which means that gravity creates pressure.
• B)the diffusion of water from one sieve-tube cell to the next.
• C)the loading of sugars into phloem at sources and removal of sugars at sinks.
• D)the active transport of water from sugar sources to sugar sinks.

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Definitions:

Participant Dropouts

Individuals who withdraw from a study or experiment before it is completed, affecting the validity of the results.

Nonequivalent Control Group Design

A quasi-experimental design where the experimental group and the control group are not created by random assignment, potentially leading to differences between groups that are not due to the experimental manipulation.

Selection Differences

Differences that arise in experimental research from the methods used to select participants for groups, potentially biasing the results.

Random Assignment

A method used in experiments to evenly distribute participants across various groups by chance, minimizing biases and ensuring groups are comparable.