The human body is composed of cells, organs, organ systems, and tissues. how are these organized? a) groups of cells form tissues. b) groups of organs form tissues. c) groups of organ systems form tissues. d) groups of tissues form organ systems.

the correct answer is option d.

an appositive is a noun, noun phrase or noun clause which follows another noun or noun phrase in order to describe it or name it another way. they are usually used between commas, brackets or dashes.

the example sentence with the correct use of commas is the following:

her uncle, the man over there in the red shirt, owns the hardware store in town.