Final answer:
Amazon's home delivery and Instacart's Whole Foods delivery are in the growth stage of market development, showing rising sales, customer adoption, and continuing enhancement to their services.
Step-by-step explanation:
Amazon's home delivery of groceries and Instacart's delivery of Whole Foods items are found on the growth stage of the market development curve. This stage is characterized by increasing sales, customer adoption, and enhancements to the product or service to meet additional customer needs. Over time, the companies have expanded their reach, invested in logistics and infrastructure, and through their economies of scale, they have continued to grow their market share. They are clearly beyond the introduction stage, as their services are widely recognized and used. They are not yet at the maturity stage where the market becomes saturated and growth slows, nor are they in decline stage where sales and market presence diminish.