This is going to take some time. Need to be careful not to miss any words. Also, some words might be repeated in different contexts, so the synonyms should fit all those instances. For example, "study" appears in "study of life" and maybe elsewhere.
1. "many benefits" could be numerous advantages 2. "convenience" becomes accessibility biology holt mcdougal pdf
"Interactive features: The Holt McDougal Biology PDF includes interactive features such as animations, videos, and quizzes that can help make learning more engaging and fun." This is going to take some time