Some Angiosperms Produce "Cluster Roots," Which Are Roots That Have

question 132

Multiple Choice

Some angiosperms produce "cluster roots," which are roots that have high metabolic rates and exude large quantities of organic acids into the soil. For the plant, what do you expect is the most useful benefit of these organic acids?

• A)They provide energy for free-living soil microbes.
• B)They provide energy for symbiotic microbes.
• C)They raise soil pH to liberate tightly bound minerals.
• D)They lower soil pH to liberate tightly bound minerals.

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Definitions:

CS

stands for Conditioned Stimulus, an originally neutral stimulus that, after association with an unconditioned stimulus, comes to trigger a conditioned response.

Higher-Order Conditioning

The phenomenon that a stimulus (CS2) can elicit a conditioned response (CR) even without being paired with the unconditioned stimulus (UCS) if the CS2 is paired with a conditioned stimulus (CS1).

Counterconditioning

The elimination of a conditioned response when the conditioned stimulus is paired with an opponent or antagonistic unconditioned stimulus

Stimulus Substitution

A theory in classical conditioning suggesting that a conditioned stimulus acts as a substitute for an unconditioned stimulus, eliciting a similar response.