Which term refers to the movement of substances through a cell membrane without the use of energy?

Correct Answer: A

Rationale: Diffusion allows substances to move passively across membranes, driven by concentration gradients, not energy. Unlike active processes, it's effortless flow. Clinicians rely on it like in oxygen uptake ensuring vital exchanges occur naturally for cellular health.

Correct Answer: D

Rationale: Parathyroid hormone (PTH) adjusts blood calcium, mobilizing it from bones when low. Unlike metabolic or sex hormones, it's a calcium gatekeeper. Nurses monitor it in bone health like osteoporosis ensuring skeletal and systemic balance.

Correct Answer: D

Rationale: A tissue is a group of similar cells with a specific function, like muscle tissue contracting. An organism is a whole living entity, an organelle is a cell component (e.g., nucleus), and an organ combines tissues. Tissues are the second organizational level after cells, foundational in anatomy for understanding how specialized functions like epithelial tissue protecting skin build complex structures.

Correct Answer: B

Rationale: The mitochondrion, a cell's energy producer, is an organelle, not an organ (A, tissue group), cell (C, whole unit), or tissue (D, cell group). Organelles are anatomy's intracellular specialists, and mitochondria's role in ATP synthesis exemplifies their functional importance, making B correct.

Correct Answer: B

Rationale: The calf is distal (farther from attachment) to the knee, which is proximal (closer to thigh attachment). It's not deep (A, depth-related), proximal, or both. Distal aligns with anatomy's limb terminology, marking the calf below the knee.