Why does fruit have seeds but vegetables do not?

This is not entirely true.

• Fruits contain the plant's seeds and are typically sweet and fleshy.
• Vegetables are the other parts of the plant, such as the leaves, stems, roots, and flowers, and are typically not sweet and fleshy.

However, there are some exceptions to this rule. For example, tomatoes and cucumbers are botanically considered fruits because they contain seeds, but they are commonly referred to as vegetables in culinary settings.