Final answer:
The main physiological effect of alcohol consumption is the depression of the central nervous system, leading to slower reaction times and reduced alertness. Excessive drinking can also lead to tolerance, withdrawal symptoms, and fetal alcohol spectrum disorder in pregnant persons.
Step-by-step explanation:
The main physiological effect of drinking alcohol is b) Depressed central nervous system. This occurs because alcohol functions as a central nervous system depressant, leading to decreases in reaction time, visual acuity, alertness, and behavioral control. Drinking also increases the risk of developing tolerance and withdrawal symptoms with repeated use, highlighting the substance's potential for abuse. In addition, alcohol can cause fetal alcohol spectrum disorder (FASD) if consumed by a pregnant person.
In terms of other physiological effects, while moderate drinking might be linked to longer lifespans and social easing, excessive alcohol use has negative impacts such as decreased body temperature and blood pH, increased urine output due to inhibition of ADH release, and increased carbon dioxide levels. It is essential to note that alcohol's effects vary depending on the individual's blood alcohol concentration (BAC), which can differ based on several factors including age, sex, and health conditions.