Nokea
What is the technical term for the free edges of your fingernails and toenails?
- A. Lunula (The lunula is the white crescent moon shape at the base of the nail)
- B. Matrix (The matrix is the area under the nail where new nail cells are produced)
- C. Hyponychium (This is the skin under the free edge of the nail)
- D. Free edge
Correct Answer: C
Rationale: The correct answer is C, hyponychium. The hyponychium is the skin under the free edge of the nail, responsible for sealing the nail to the fingertip and protecting the nail bed from bacteria and debris. The lunula (choice A) refers to the white crescent moon shape at the base of the nail. The matrix (choice B) is the area under the nail where new nail cells are produced. The free edge (choice D) is the part of the nail that extends beyond the fingertip or toe.
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Who is credited with the discovery of nuclear fission?
- A. Marie Curie
- B. Albert Einstein
- C. Enrico Fermi
- D. Ernest Rutherford
Correct Answer: C
Rationale: Enrico Fermi is credited with the discovery of nuclear fission. In 1934, Fermi bombarded uranium with neutrons, leading to the splitting of the uranium nucleus and the release of energy. This groundbreaking discovery laid the foundation for the development of nuclear power and weapons. Marie Curie is known for her pioneering research on radioactivity, but she did not discover nuclear fission. Albert Einstein made significant contributions to physics, including the theory of relativity, but he was not credited with the discovery of nuclear fission. Ernest Rutherford conducted the famous gold foil experiment and made contributions to the understanding of the atom's structure, but he did not discover nuclear fission.
What is the primary function of the epiglottis in the respiratory system?
- A. Filtration of air
- B. Production of mucus
- C. Prevention of food entering the trachea
- D. Oxygen exchange in the alveoli
Correct Answer: C
Rationale: The primary function of the epiglottis in the respiratory system is to prevent food from entering the trachea. During swallowing, the epiglottis covers the opening of the trachea, guiding food down the esophagus to the stomach and preventing it from entering the airway. This mechanism safeguards the respiratory system from foreign objects, ensuring proper air passage and avoiding potential choking hazards. Choices A, B, and D are incorrect: A) Filtration of air is mainly performed by the nasal hairs and the mucous membranes of the respiratory tract. B) Production of mucus is primarily carried out by the mucous glands in the respiratory system to trap particles and humidify the air. D) Oxygen exchange in the alveoli occurs in the lungs and is related to the process of respiration, not the function of the epiglottis.
What is the mass number of an element?
- A. The number of protons in an atom's nucleus.
- B. The number of neutrons in an atom's nucleus.
- C. The number of electrons in an atom's valence shell.
- D. The number of isotopes of an element.
Correct Answer: B
Rationale: The mass number of an element represents the total number of protons and neutrons in an atom's nucleus. It specifically focuses on the number of neutrons in an atom's nucleus, which contributes to the overall mass of the atom. Therefore, the mass number is not solely determined by the number of protons, electrons, or isotopes. Choice A is incorrect because it refers to the atomic number, which is the number of protons in an atom's nucleus. Choice C is incorrect as the number of electrons in the valence shell is related to the atom's reactivity and bonding behavior, not the mass number. Choice D is incorrect because the mass number does not represent the number of isotopes of an element, but rather the sum of protons and neutrons in an atom's nucleus. Thus, option B, the number of neutrons in an atom's nucleus, is the correct choice.
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.
Cartilage, found in joints and the ear, is a type of:
- A. Epithelial tissue
- B. Connective tissue
- C. Muscle tissue
- D. Nervous tissue
Correct Answer: B
Rationale: Cartilage is a type of connective tissue that provides support and flexibility to various parts of the body, such as joints and the ear. It is composed of cells called chondrocytes embedded in a matrix of collagen and proteoglycans. Epithelial tissue covers body surfaces, muscle tissue is involved in movement, and nervous tissue transmits signals. The correct answer is connective tissue because cartilage serves a supportive function in the body.