I find it useful, at the start of the course, to define some important terms and give some simple examples to which students can identify, e.g. the water cycle. This means that when you revisit the concepts in later topics, e.g. ecosystems, then the students are already familiar with the terms.This page includes significant ideas from suptopics 1.2 and 1.3 as they really do overlap.Here"s a review for students What is...