Connective tissue holds together and gives shape to body organs and tissues. It also holds organs in place and supports the body. Compared with other types of tissue, connective tissue has relatively few cells and much intercellular substance (material outside the cells). Scientists divide connective tissue into three groups, according to the hardness of the intercellular substance. These groups are (1) soft connective tissue proper, (2) firm cartilage, and (3) hard bone.