Answer:
a. food pellet
Explanation:
In classical conditioning, an unconditioned stimulus is the stimulus that naturally elicits an unconditioned response. The unconditioned stimulus is usually paired with a neutral stimulus, and after pairing with a neutral stimulus, the neutral stimulus becomes a conditioned stimulus that elicits a conditioned response alone.
In the experiment described above in the question, <em>the unconditioned stimulus is the food pellet,</em> which naturally elicits the response of the rat to wait at the far left corner of the cage. The neutral stimulus which is paired with the food pellet is the vanilla scent, which now becomes the conditioned response, when paired alone.
Carbon dioxide concentrations in soil are higher than in the atmosphere because of respiration of the plants, their roots. Also, CO2 is inhigherr concentration because of the decomposition of organic matter. Decomposition of organic matter produce more CO2 because of increased microbial activity. CO2 concentrations can change as a result of temperature change or different soil structure. Composition of air in soil and atmosphere of CO2 is
<span>Soil Air: 0.25% Atmosphere: 0.04%.</span>
