Final answer:
The symptoms of moderate-severe dehydration in infants include dry mouth and tongue, sunken fontanelle, decreased urine output, frequent vomiting, dizziness when standing up, and diarrhea that lasts more than 3 days.
Step-by-step explanation:
Severe dehydration in infants can present with symptoms such as dry mouth and tongue, sunken fontanelle, and decreased urine output. These signs indicate that the baby is not getting enough fluids and is experiencing a deficit in water and electrolytes in their body. Other possible symptoms of moderate-severe dehydration in infants can include frequent vomiting that prevents keeping liquids down, dizziness when standing up, a very dry mouth and throat, and diarrhea that lasts more than 3 days.