Correct Answer: B

Rationale: The correct answer is B: Protons and neutrons only. Electrons are located outside the nucleus in electron shells. Protons and neutrons are the subatomic particles found within the nucleus of an atom. Protons carry a positive charge, while neutrons are neutral. These particles contribute to the mass and stability of the nucleus. Choice A is incorrect because electrons are not part of the nucleus. Choice C is incorrect as electrons are not found within the nucleus, only protons and neutrons. Choice D is incorrect as protons and neutrons are indeed constituents of an atomic nucleus.

Correct Answer: C

Rationale: Translation is the process by which the genetic information carried by mRNA is decoded to synthesize a polypeptide chain. This essential process occurs at the ribosomes within the cell. The product of translation from an RNA template is a polypeptide, not DNA, lipid, or carbohydrate. DNA is involved in transcription, lipids are not directly produced in translation, and carbohydrates are not synthesized through translation. Therefore, the correct product resulting from translation from an RNA template is a polypeptide, making choice C, 'Polypeptide,' the correct answer.

Correct Answer: C

Rationale: The nasal passages are responsible for humidifying and warming inhaled air before it reaches the lungs. The mucous membranes in the nasal passages help add moisture to the air and warm it to body temperature. This process is crucial for protecting the lung tissues from potential damage caused by cold and dry air, ensuring optimal conditions for respiration. The trachea (Choice A) is responsible for conducting air to and from the lungs, the larynx (Choice B) is involved in sound production and protecting the airway during swallowing, and the bronchi (Choice D) are the branches of the trachea that further divide to deliver air to the lungs but are not primarily responsible for humidifying and warming inhaled air.

Correct Answer: D

Rationale: A) Insulin is a hormone, not a fibrous protein. It is produced in the pancreas and regulates blood sugar levels. B) Keratin is a fibrous structural protein found in hair, nails, and the outer skin layer, providing strength and protection. C) Hemoglobin is a globular protein in red blood cells responsible for oxygen transport; it is not fibrous. D) Collagen is a fibrous protein found in tendons, ligaments, and skin, offering strength and structure to connective tissues. Therefore, the correct answer is collagen, making it the main component of various connective tissues.

Correct Answer: B

Rationale: The correct answer is 'Remodeling.' Remodeling is the process of breaking down and rebuilding bone tissue. Ossification is the process of bone formation, not breaking down and rebuilding bone tissue. Calcification involves the deposition of calcium salts in tissues, but it is not specifically related to breaking down and rebuilding bone tissue. Osteoporosis is a condition characterized by decreased bone density leading to increased bone fragility, not the process of breaking down and rebuilding bone tissue.