Which nervous system response causes an increase in blood pressure, pupil dilation, and dry mouth due to anxiety?

The sympathetic nervous system is responsible for preparing the body for the "fight or flight" response during stressful situations. When activated, it triggers a series of physiological changes aimed at enhancing the body's ability to respond to perceived threats. This includes increasing heart rate and blood pressure, dilating the pupils to allow more light in for better vision, and reducing saliva production, which can lead to dry mouth. These changes are primarily mediated by the release of adrenaline and other stress hormones.

In contrast, the voluntary nervous system is involved in conscious control of skeletal muscles and is not directly related to the autonomic responses of the body. The limbic system, while it plays a significant role in emotions and behavior, does not directly control the physiological responses described in the question. The cognitive aspect refers to mental processes like thinking, learning, and memory, which do not account for the immediate physiological changes evident during anxiety responses. Thus, the sympathetic nervous system is the correct choice as it is the primary system that governs these Fight-or-Flight reactions.