Final answer:
Alcohol has several negative effects on the body when operating a vessel, including impaired judgment and coordination, decreased reaction time, and reduced ability to concentrate.
Step-by-step explanation:
When operating a vessel, alcohol can have several negative effects on the body. It can impair judgment and coordination, which can make it difficult to make good decisions and control the vessel properly. It can also decrease reaction time, which means that it will take longer to respond to any potential dangers or obstacles. Additionally, alcohol can reduce the ability to concentrate, which can make it harder to stay focused on operating the vessel safely. Therefore, the correct answer is 4) All of the above.