Basic Tissue Types. All of the various tissues of the human body can be categorized into four basic tissue types. All organs are built of these four tissues, which have consistent characteristics and arrangements from organ to organ. Thus an appreciation of the major features of these four basic tissue types can greatly simplify your understanding of the cellular composition of the many organ systems. 1  OVERVIEW.
Definition of session for English Language Learners : a period of time that is used to do a particular activity : a formal meeting or series of meetings of a group of people (such as a court of law or legislature)
Definition of school for Students. 1  1 : a place for teaching and learning. 2  2 : a session of teaching and learning night school You'll be late for school. 3  3 : schoolhouse. 4  4 : the teachers and pupils of a school The entire school was at the rally. 5  5 : a group of persons who share the same opinions and beliefs a new school of philosophy.