1) Teachers need to know their students' backgrounds, skills, interests, achievements and how these impact learning. They should understand students' physical, social and intellectual development.
2) Teachers must know and respect students' diverse backgrounds and understand how these affect learning. They should also understand different learning approaches and strategies to address student needs.
3) The document discusses several theories about student development and learning, including Vygotsky's socio-cultural theory, Maslow's hierarchy of needs and Gardner's theory of multiple intelligences. It provides examples of how to apply these theories to meet different students' needs.