Which phase of the cardiac cycle involves ventricular relaxation and filling?

A. Ball and socket joints: Ball and socket joints, such as the shoulder and hip, allow for a wide range of movement in multiple directions. They are synovial joints with a fluid-filled cavity, not primarily connected by cartilage for limited motion.

B. Synovial joints: Synovial joints have a joint cavity filled with synovial fluid and permit free movement. They include hinge, pivot, and ball-and-socket joints, providing more mobility than partial-movement joints.

C. Cartilaginous joints: Cartilaginous joints are connected by cartilage, allowing limited or partial movement. Examples include intervertebral discs and the pubic symphysis, providing stability while permitting slight flexibility.

D. Fibrous joints: Fibrous joints are connected by dense connective tissue and allow little to no movement. Examples include sutures in the skull, which provide strength and protection rather than flexibility.

A. Hormonal secretion: While bone tissue does secrete certain hormones like osteocalcin, hormonal secretion is not its primary function. The main roles of bones are structural support, movement, and protection.

B. Digestive enzyme production: Digestive enzymes are produced by organs such as the pancreas and stomach. Bone tissue does not contribute to digestion or enzyme production.

C. Oxygen transport: Oxygen transport is carried out by red blood cells in the bloodstream. Bone tissue provides a site for blood cell production in the marrow but does not directly transport oxygen.

D. Protection of internal organs: One of the primary functions of bone tissue is to protect vital internal organs. For example, the skull shields the brain, and the ribcage protects the heart and lungs, while bones also provide structural support and enable movement.