Complex sentence: Because it restricts the meaning of "vegetable", this adjective clause is called a restrictive clause; it is essential to the meaning of the main clause and uses no commas (and correspondingly, does not experience a pause when spoken).
Split into simpler sentences: Because it restricts the meaning of "vegetable", this adjective clause is called a restrictive clause. It is essential to the meaning of the main clause and uses no commas (and correspondingly, does not experience a pause when spoken).