Final answer:
The sympathetic division of the ANS is called the "fight-or-flight" system because it increases tissue metabolism and alertness, preparing the body to respond to threats with either confrontation or escape.
Step-by-step explanation:
The sympathetic division of the ANS is known as the "fight-or-flight" system because it prepares the body for quick action in situations perceived as threatening. It brings about an increase in tissue metabolism and alertness. The right answer to the question is D) It increases tissue metabolism and alertness. When triggered, it causes physiological changes such as an accelerated heart rate, dilation of airways, increased blood flow to muscles, and decreasing blood flow to the gastrointestinal (GI) tract. These changes optimize the body's ability to either confront the threat ('fight') or to run away from it ('flight').
During these situations, adrenaline (epinephrine) is released, which further stimulates various organs in the body to respond accordingly. The sympathetic nervous system's widespread effects result from the extensive branching patterns of its neurons, which allow a single preganglionic neuron to influence multiple organs simultaneously.