Nokea
Which of the following minerals is important for bone health and is stored in bones by the skeletal system?
- A. Iron
- B. Sodium
- C. Calcium
- D. Magnesium
Correct Answer: C
Rationale: The correct answer is Calcium (Choice C). Calcium is essential for bone health and is stored in bones by the skeletal system. Bones act as a reservoir for calcium, playing a critical role in maintaining bone strength and density. Iron, sodium, and magnesium are important for various bodily functions but are not primarily stored in bones for bone health. Iron is crucial for oxygen transport, sodium helps regulate fluid balance, and magnesium is involved in over 300 enzymatic reactions in the body.
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What do Newton's rings visually demonstrate?
- A. Diffraction
- B. Doppler effect
- C. Polarization
- D. Thin-film interference
Correct Answer: D
Rationale: Newton's rings are a series of concentric colored rings observed when light is reflected between a spherical surface and a flat surface. This phenomenon is a result of thin-film interference, where light waves reflecting off the two surfaces interfere with each other constructively or destructively, leading to the observed pattern of rings. Diffraction, polarization, and the Doppler effect are not related to the specific phenomenon of Newton's rings. Diffraction refers to the bending of waves around obstacles, polarization deals with the orientation of electromagnetic waves, and the Doppler effect relates to the change in frequency of waves due to motion. Therefore, the correct answer is thin-film interference, as it precisely describes the phenomenon observed in Newton's rings.
What is the pH of a solution with a hydrogen ion concentration of (1x10^{-9}) M?
- A. 5
- B. 7
- C. 9
- D. 11
Correct Answer: C
Rationale: The pH of a solution can be calculated using the formula: pH = -log[H+]. Given that the hydrogen ion concentration is \(1 \times 10^{-9}\) M, the pH can be calculated as pH = -log(1 x 10^-9) = 9. Therefore, the correct answer is C) 9.
What is the main consequence of a malfunctioning thyroid gland that produces abnormally low levels of thyroid hormones?
- A. Increased energy levels and weight loss
- B. Decreased heart rate and body temperature
- C. Enhanced muscle growth and bone development
- D. Faster metabolism and heightened alertness
Correct Answer: B
Rationale: The correct answer is B: Decreased heart rate and body temperature. A malfunctioning thyroid gland that produces abnormally low levels of thyroid hormones leads to hypothyroidism, resulting in decreased metabolic activity. This reduction in metabolic rate can cause a decreased heart rate and lower body temperature. Choices A, C, and D are incorrect because hypothyroidism typically manifests as symptoms such as fatigue, weight gain, cold intolerance, bradycardia, and decreased body temperature, rather than increased energy levels, enhanced muscle growth, faster metabolism, or heightened alertness.
What is the name for the flexible connection between bones at the wrist or ankle?
- A. Ligament
- B. Tendon
- C. Fascia
- D. Synovial joint
Correct Answer: A
Rationale: The correct answer is A: Ligament. Ligaments are tough bands of tissue that connect bones to other bones at joints, providing stability and support. In the case of the wrist or ankle, ligaments play a crucial role in maintaining the structural integrity and allowing for proper movement of these joints. Tendons (option B) connect muscles to bones, not bones to bones. Fascia (option C) is a connective tissue that surrounds muscles and other structures, not connecting bones at joints. A synovial joint (option D) is a type of joint that allows for movement between bones, but it is not the flexible connection between bones at the wrist or ankle.
What is the name of the cartilage flap that covers the trachea during swallowing, preventing food from entering the airway?
- A. Epiglottis
- B. Glottis
- C. Larynx
- D. Pharynx
Correct Answer: A
Rationale: The correct answer is A: Epiglottis. The epiglottis is a cartilage flap located at the base of the tongue that covers the trachea during swallowing. Its primary function is to prevent food and liquids from entering the airway and instead directs them towards the esophagus. The glottis (choice B) refers to the space between the vocal cords in the larynx. The larynx (choice C) is the voice box containing the vocal cords responsible for phonation. The pharynx (choice D) is the throat region connecting the mouth and the esophagus, playing a role in both digestion and respiration.