What is the difference between fruit and vegetables?

The podcast explores the difference between fruits and vegetables through a fantastical journey. Costa uses "magic compost" to shrink himself and two companions, Millie and Xavier, transporting them to a world made of fruits and vegetables. They encounter Cosmo, a giant caterpillar, who leads them to discover that fruits, botanically speaking, are defined by having seeds and developing from the flower of a plant, using the example of an apple's star-shaped core. Vegetables are categorized into roots, leaves, and stems, representing edible plant parts without seeds. The group also conducts an experiment using corn to further illustrate the distinction. Despite the scientific definitions, the podcast acknowledges that flavor plays a significant role in how people commonly differentiate between fruits and vegetables.