The Ideal Christmas Tree Has a Conical Shape

question 41

Multiple Choice

The ideal Christmas tree has a conical shape. The top of the tree is pointed and narrow, with clear apical dominance, and the bottom of the tree is wide, with extensive lateral branching. Certain evergreen species are suitable for use as Christmas trees because they have this shape normally and thus require little pruning or training as they grow. For example, spruces and firs are often grown as Christmas trees, whereas yews and longleaf pines are not. Based on this information, spruces and firs are likely to have

• A) high levels of auxins near the top and low levels of cytokinins at the bottom of the tree.
• B) low levels of auxins near the top and high levels of cytokinins at the bottom of the tree.
• C) high levels of auxins near the top and high levels of cytokinins at the bottom of the tree.
• D) low levels of auxins near the top and low levels of cytokinins at the bottom of the tree.

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Definitions:

Pain

An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.

Conditioned Stimulus Preexposure Effect

A phenomenon where exposure to the conditioned stimulus prior to pairing it with the unconditioned stimulus decreases the effectiveness of conditioning.

Conditioning

The process of learning associations between environmental stimuli and behavioral responses, fundamental to behavioral psychology.

Stimulus

Any event or situation that evokes a response from an organism.