Another option for a college textbook: Conceptual Integrated Science. My stepdaughter used this text last year in an introductory science course for education students. Also, in most Canadian provinces, students take general science in 9th and 10th, then pick one or two areas to study in 11th and 12th. If the college textbooks are too much, a 9th or 10th grade textbook might be a better fit. I don't have any specific recommendations, but I believe our schools use McGraw-Hill.