Answer:
The septum
Explanation:
The septum is a thick wall of muscle that divides the heart. It separates the left and right sides of the heart.
The joint cavities are composed of two bones covered by the hyaline cartilage. The joint cavities allow for the movement of the two articulated bones. The fibrous and the cartilaginous bones have no joint cavities as they require little to no movement. These joints are connected tightly by the cartilage, such as in the spinal column. if the joint cavities were present in these joints, then these structures will not be held tightly and hence, they could not perform their function well.
Hence, the answer is 'the fibrous and cartilaginous joints will not be able to perform their function if they had joint cavities'.
The answer is A, with no place to live, they either died or moved to other places.
