What type of gland secretes hormones directly into the bloodstream?

Correct Answer: B

Rationale: Endocrine glands secrete hormones (e.g., thyroid's thyroxine) directly into the bloodstream, lacking ducts, for systemic effects like metabolism regulation. Exocrine glands use ducts (e.g., salivary glands). Sebaceous and sweat glands , both exocrine, secrete oil and sweat externally. Endocrine glands' ductless, blood-mediated delivery, per glandular classification, makes 'b' the correct type.

Correct Answer: A

Rationale: Osteoporosis is a condition where bones weaken and become brittle from reduced density, increasing fracture risk, often age-related or hormonal. It's not a fracture , infection (c, osteomyelitis), or joint disorder (d, arthritis). Its systemic bone loss, per pathology, makes 'a' correct.

Correct Answer: B

Rationale: The shoulder's glenohumeral joint is a ball-and-socket, with the humerus's ball in the scapula's glenoid, allowing wide motion (e.g., rotation). Hinge is elbow, pivot is atlas-axis, saddle is thumb. Ball-and-socket's range, per joint types, makes 'b' correct.

Correct Answer: C

Rationale: The occipital bone forms the skull's base, with the foramen magnum for spinal cord exit, supporting the brain posteriorly. Temporal is lateral, frontal is anterior, maxilla is facial. Occipital's foundational role, per skull anatomy, makes 'c' correct.

Correct Answer: D

Rationale: The skeletal system provides structural support via bones and enables movement by anchoring muscles at joints (e.g., femur in walking). The cardiovascular system circulates blood, not support/movement. The endocrine system regulates via hormones. The muscular system moves but relies on skeletal framework. Skeletal system's foundational role, per body systems, makes 'd' correct.