You are on a field trip and are recording the salinity levels of the water. what are you measuring?

there are 35 white marbles

step-by-step explanation:

y- yellow marbles

4y + 5 = 45

subtract 5 from both sides

4y = 40

divide for from both sides

y = 10

plug in 10 to get 40 yellow marbles then subtract by 5 to get 35 marbles

thus there are only 10 yellow marbles

1. efficient use of space

2. elimination of groundwater contamination

3. energy generation

4. lower carbon footprint