Assertion: Cartilage (protein matrix) and bone (calcium matrix) are rigid connective tissue.
Reason: Blood is connective tissue in which plasma is the matrix.
Both Assertion and Reason are correct but Reason is not the correct explanation of Assertion.
Cartilage is a semi-rigid connective tissue that is not as stronger as the bone but more flexible and resilient. Bone is sturdy and rigid due to deposition of minerals in the matrix.