Humans have the most urgent need for a continuous supply of

Correct Answer: C

Rationale: Humans need oxygen most urgently, surviving only minutes without it, as it fuels cellular respiration (ATP production) via lungs. Food sustains days, water hours to days, nitrogen isn't directly needed (it's in air, not a pressing requirement). Oxygen's immediate necessity, per survival physiology, makes 'c' correct.

Correct Answer: C

Rationale: Warming up, athletes perform movements like stretching or light jogging, exemplifying treppe the staircase effect. Initial contractions increase force progressively as calcium accumulates and muscle fibers activate more efficiently, enhancing performance without fatigue. Isotonic contractions shorten muscles against constant load (e.g., lifting), while isometric maintain length under tension (e.g., planks) both common in exercise but not warm-up specific. Twitch is a single, brief contraction, not sustained activity. Tetanus involves maximal, fused contractions from rapid stimuli, typical of intense effort, not warm-ups. Treppe, observed in physiology labs, boosts contractility over successive stimuli at low frequency, warming muscle tissue, increasing blood flow, and optimizing enzyme activity. This priming contrasts with isotonic's dynamic shortening or tetanus's sustained force, aligning with warm-ups' preparatory role. Studies show treppe elevates twitch force 20-50% early on, a subtle yet critical enhancement for athletes, distinct from static or exhaustive contraction types.

Correct Answer: D

Rationale: Goniometry is a clinical tool used to assess joint mobility, specifically the extent to which a joint can move through its normal range. This measurement is critical in evaluating conditions affecting joints, such as arthritis or post-injury stiffness, and in tracking rehabilitation progress. Bone strength relates more to density and structural integrity, typically assessed via imaging like a DEXA scan, not goniometry. Muscle density isn't a standard metric in this context and is unrelated to joint angles. Muscle strength, while important, is measured through manual testing or dynamometry, not by gauging joint movement. Range of motion is the precise focus of goniometry, as it quantifies the degrees of flexion, extension, or rotation, providing objective data for treatment planning. The other options misalign with the tool's purpose, which is rooted in joint function rather than bone or muscle properties.

Correct Answer: A

Rationale: Quadriceps and gluteal exercises target thigh and buttock strength, often used in rehabilitation. Straightening the leg and tensing muscles while raising the heel (quadriceps setting) contracts the quadriceps against gravity, and gluteal engagement occurs when squeezing the buttocks, both doable lying down. Flexing the leg and pulling it back with hands targets hamstrings and hip flexors, not primarily quadriceps or glutes. Straightening legs and knees is vague and incomplete without specifying tension or lifting, lacking the active contraction needed. The first method effectively isolates and strengthens the intended muscle groups, promoting stability and recovery, especially post-injury or surgery, with clear, executable steps.

Correct Answer: A

Rationale: Calcium-rich foods are vital for osteoporosis prevention, and dairy like milk is a primary source, alongside certain fish like salmon, which contains bones rich in calcium when grilled or canned. Green beans add nutrients but little calcium. This combo maximizes intake effectively. Hamburger with milk offers calcium from milk, but the patty and chips contribute minimally. Chicken and salad with fruit punch lack significant calcium, as punch isn't a source. The BLT with milk provides calcium from milk, but bacon and tomatoes don't add much. Salmon and milk together demonstrate a stronger understanding of boosting calcium through diverse, potent sources, aligning with bone health goals.