Final answer:
Megan should use gallons to record the daily milk production from her 85 cows, as it is the most appropriate unit for measuring large volumes of liquid.
Step-by-step explanation:
When Megan is considering how to record the amount of milk produced by her 85 cows, she should focus on a unit of measurement that reflects the sizable quantity of milk produced daily. In this scenario, the most appropriate unit for measuring a large volume of liquid like milk is gallons. Keeping track of daily milk production in gallons allows for a consistent and manageable record-keeping process, which is important for dairy farm operations that involve selling milk and turning it into products like yogurt and cheese.