Sympathetic activation can increase one of the following:

In the context of the sympathetic nervous system, activation typically prepares the body for "fight or flight" responses. One of the physiological responses during sympathetic activation is an increase in sweating. This occurs as part of the body's mechanism to regulate temperature and enhance physical performance during stress or danger. The sympathetic nervous system stimulates sweat glands, which helps cool the body during heightened physical activity or emotional stress.

On the other hand, bronchoconstriction, decreased skin temperature, and reduced stomach motility are typically associated with parasympathetic activation or a homeostatic state rather than sympathetic activation. The sympathetic nervous system generally promotes bronchial dilation to allow more air into the lungs, increases skin temperature through blood flow changes, and decreases stomach motility as digestion is deprioritized during times of stress. Thus, the correct answer highlights the role of sympathetic activation in increasing sweating in response to stress.