To find the elevation of base camp after Helene descends 46 feet from her starting elevation of 33 feet above sea level, you can simply subtract the descent from the starting elevation:
Starting elevation: 33 feet above sea level
Descent: 46 feet
Calculate the elevation of base camp: \[ 33 \text{ feet} - 46 \text{ feet} = -13 \text{ feet} \]
A negative elevation indicates that the elevation is below sea level. Therefore, the elevation of base camp is 13 feet below sea level.
The correct response is: 13 feet below sea level.