In all connective tissues, the cells secrete fibres of structural proteins called collagen or elastin, which provide strength, elasticity, and flexibility to the tissue. Identify the connective tissue which is an exception to this rule.

Step-by-step solution

According to the NCERT, in all connective tissues except blood, the cells secrete fibres of structural proteins called collagen or elastin. Blood is a fluid connective tissue containing plasma, red blood cells (RBC), white blood cells (WBC) and platelets, and it lacks fibre-secreting cells (fibroblasts). Cartilage, bone, and areolar tissue all contain cells that secrete structural fibres. Answer: Blood