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)
School holiday. School holidays (also referred to as vacations, breaks, and recess) are the periods during which schools are closed. The dates and periods of school holidays vary considerably throughout the world, and there is usually some variation even within the same jurisdiction.