What is a tissue?

Correct Answer: A

Rationale: A tissue is a group of similar cells with a common function, like muscle or epithelial tissue, forming the basic structural units between individual cells and organs in the body's hierarchy. A type of organ is incorrect organs comprise multiple tissues (e.g., skin includes epithelium and connective tissue). A fluid might describe blood, a tissue, but not all tissues are fluids (e.g., bone). A structural protein like collagen exists within tissues, not as tissue itself. The definition of tissue as cellular aggregates with shared roles, per histology, makes 'a' the correct answer.

Correct Answer: D

Rationale: The skeletal system's primary functions include all: hormone production (e.g., osteocalcin from osteoblasts), blood cell production (marrow in long bones), and protection/support (e.g., skull, rib cage), a comprehensive role. No single function excludes others bones multitask. This broad scope, per skeletal physiology, makes 'd' correct.

Correct Answer: B

Rationale: The axial skeleton includes the skull, vertebral column, and rib cage, forming the body's central axis for support/protection. Appendicular is limbs/girdles. Pectoral and pelvic girdles are appendicular parts. Axial's midline role, per skeletal division, makes 'b' correct.

Correct Answer: B

Rationale: The hyoid bone, free-floating in the neck, anchors tongue and larynx muscles (e.g., genioglossus), aiding speech/swallowing. It doesn't support the skull , protect thorax , or form skull base (d, occipital). Its muscular role, per anatomy, makes 'b' correct.

Correct Answer: D

Rationale: Paranasal sinuses (frontal, maxillary, etc.) warm/humidify air , produce mucus to trap debris, and lighten the skull (not a, reducing weight). All functions apply, enhancing respiration and skull structure, making 'd' correct.