Which principle of instruction is illustrated by requiring learners to complete basic algebra practice before advanced tutorials?

The principle of instruction that is illustrated by requiring learners to complete basic algebra practice before advancing to more complex tutorials is activation. This principle emphasizes the importance of engaging learners' prior knowledge and skills before introducing new content. By ensuring that learners have a solid understanding of basic algebra, they are better prepared to tackle more challenging material. This approach helps to build a strong foundation, allowing learners to connect new concepts to what they already know, which enhances their overall learning experience and understanding.

In contrast, while the other principles like problem-centered learning could involve solving real-world problems, integration focuses on linking ideas, and demonstration revolves around showing learners how to perform tasks, they don't specifically address the concept of activating existing knowledge as a prerequisite for new learning, making activation the most fitting choice in this context.