Ryan conducted a 6-day study observing the effects of an organic plant food on the growth of his sprouting bean plant. He tracked these two pieces of information: Which statement is true about the relationship between the amount of plant food remaining and the number of days?

This relationship is not a function because only one amount of plant food remains each day.
This relationship is not a function because more than one amount of plant food remains each day.
This relationship is a function because more than one amount of plant food remains each day.
This relationship is a function because only one amount of plant food remains each day.