Are avocados, cucumbers, eggplants, peppers, pumpkins, squash, tomatoes, and zucchini fruits or vegetables?

All are fruits.

A fruit is the part of a plant involved in its reproduction; fruits contain seeds. So, although these foods are not sweet like an apple or an orange, botanically speaking, all are fruits. Other parts of plants are vegetables: the stems (asparagus, celery), roots (beet, carrot), flowers (broccoli, cauliflower), leaves (greens), and bulbs (garlic) or tubers (potato, sweet potatoes, yams) that grow underground. When it comes to cancer-fighting, it doesn't matter how they're classified. They all protection.