Final answer:
The underlying assumption of this advertising campaign is that focusing on the health benefits of drinking the smoothie and the science behind the nutrition will be key to its success.
Step-by-step explanation:
The underlying assumption of this advertising campaign is that focusing on the health benefits of drinking the smoothie and the science behind the nutrition will be key to its success. By highlighting the health benefits, the advertisers believe that they can convince consumers to choose this smoothie blend over other options. They are relying on the assumption that consumers value the science behind the nutrition and are willing to make purchasing decisions based on that information.