Sandy Had Learned That If Her Mother Was Smiling at Her

question 7

Multiple Choice

Sandy had learned that if her mother was smiling at her when she came into the kitchen,it meant that Sandy would probably be given a treat to eat if she asked nicely.But if her mother was frowning,she would not give Sandy anything and instead would shoo her away.Sandy's mother's facial expression was serving as a __________.

• A)conditioned stimulus.
• B)discriminative stimulus.
• C)positive reinforcer.
• D)negative reinforcer.

---

Definitions:

Improving Food Crops

The scientific and agricultural practice of modifying plant species to enhance their yield, nutritional value, and resistance to pests and diseases.

Plant Cells

Eukaryotic cells that are part of a plant, characterized by a cell wall, chloroplasts for photosynthesis, and a large central vacuole.

Stoma

Tiny openings or pores found on the surface of leaves and stems that allow for gas exchange between the plant and its environment.

Guard Cells

Specialized cells in the epidermis of leaves, stems, and other organs that regulate gas exchange and water loss by controlling the opening and closing of stomata.