Final answer:
The major distinction between the connective tissues in an animal and other main tissue types is the amount of extracellular matrix in CT. Connective tissues feature cells dispersed within an ECM that facilitates various functions such as support, transport, and energy storage, differing significantly from the tightly packed cells in other tissue types.
Step-by-step explanation:
A major distinction between the connective tissues (CT) in an animal and other main tissue types such as epithelium, nervous tissue, or muscle is the amount of extracellular matrix (ECM) in CT. Unlike other tissues that are composed mostly of tightly packed cells, connective tissue is comprised of cells that are embedded in a substantial amount of ECM, which is secreted by the cells themselves. This matrix includes protein fibers and a ground substance that can range from fluid to mineralized and solid, giving the connective tissues various functions from supporting and protecting organs to storage and transport of energy molecules.
Connective tissues vary widely in their composition and structure, which correspond to their diverse functions. The connective tissues include several types, such as loose and dense connective tissue, cartilage, bone, and fluid tissue like blood and lymph. For instance, whereas adipose tissue serves to store energy and is a type of loose connective tissue with less ECM, bone is a supportive tissue characterized by a rigid, mineralized matrix. The functionality of connective tissues is largely attributable to their ECM, which is not a characteristic of other tissue types.