Final answer:
A juice box with less packaging is better because it allows for more space for juice within the same total volume, paralleling the concept of more efficient packing in marbles or atoms. Jesse in the mailroom should use kilograms to weigh a package for postage as it fits the size and weight of books and documents.
Step-by-step explanation:
When comparing two juice boxes with the same volume, the one with less packaging would generally be considered better. This is because, with less packaging, there is more space available for the juice itself, analogous to how marbles packed in a hexagonal arrangement are more efficient, leading to a larger quantity of marbles (or atoms in atomic packing) within the same area.
Similarly, for the juice boxes, more packaging means less space for the juice if the total volume is constant. In the case of Jesse in the mailroom, to determine the postage for a package containing books and documents, he should use the metric unit of kilograms as this unit is appropriate for the size and weight involved in the shipment of such items.