Nokea
An atom has 2 protons, 4 neutrons, and 2 electrons. What is the approximate atomic mass of this atom?
- A. 2
- B. 4
- C. 6
- D. 8
Correct Answer: D
Rationale: The atomic mass of an atom is the sum of the protons and neutrons in its nucleus. In this case, the atom has 2 protons and 4 neutrons, totaling 6 particles in the nucleus. Therefore, the approximate atomic mass of this atom is 6, making choice C incorrect. The number of electrons does not significantly contribute to the atomic mass, as they are much lighter and located in the electron cloud surrounding the nucleus. Choices A, B, and C are incorrect as they do not reflect the correct calculation of atomic mass based on protons and neutrons only.
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Which of the following best describes a function carried out by the circulatory system and the integumentary system working together?
- A. Removal of excess heat from the body
- B. Hormonal regulation of blood pressure
- C. Transport of oxygen in the body
- D. Production of red blood cells in the bone marrow
Correct Answer: A
Rationale: The correct answer is A: Removal of excess heat from the body. The circulatory system, which includes blood vessels and the heart, works with the integumentary system, which consists of the skin, to regulate body temperature by removing excess heat. This process involves blood vessels near the skin's surface dilating to release heat and constricting to conserve heat, a mechanism crucial for maintaining homeostasis. Option B, Hormonal regulation of blood pressure, is incorrect as it does not accurately describe the collaborative function of these systems in regulating body temperature. Option C, Transport of oxygen in the body, is incorrect as it focuses on a different function of the circulatory system. Option D, Production of red blood cells in the bone marrow, is incorrect as it pertains to the skeletal and hematopoietic systems, not the circulatory and integumentary systems working together to regulate body temperature.
Which of the following body systems controls fluid loss, protects deep tissues, and synthesizes vitamin D?
- A. The skeletal system
- B. The muscular system
- C. The lymphatic system
- D. The integumentary system
Correct Answer: D
Rationale: The integumentary system is responsible for controlling fluid loss through sweat, protecting deep tissues as the body's first line of defense, and synthesizing vitamin D when exposed to sunlight. The skin, hair, nails, and associated glands make up the integumentary system, which plays a crucial role in maintaining homeostasis and overall health. The skeletal system (Choice A) provides structural support and protection for internal organs but does not directly control fluid loss, protect deep tissues, or synthesize vitamin D. The muscular system (Choice B) is responsible for movement and stability but is not involved in the functions described. The lymphatic system (Choice C) is primarily responsible for immunity and fluid balance, not the specific functions mentioned in the question.
Which of the following components of the human integumentary system is the deepest?
- A. Stratum basale
- B. Epidermis
- C. Hypodermis
- D. Dermis
Correct Answer: C
Rationale: The hypodermis is the deepest layer of the integumentary system, located below the dermis. It serves as a layer of fat that helps insulate the body, store energy, and provide cushioning. The stratum basale is the deepest layer of the epidermis, not the entire integumentary system. The epidermis is the outermost layer of the skin, followed by the dermis, and then the hypodermis. Therefore, the correct answer is the hypodermis (choice C). Choices A, B, and D are incorrect as they do not represent the deepest layer of the integumentary system.
Two isotopes of the same element have different numbers of:
- A. Electrons
- B. Protons
- C. Neutrons
- D. Nuclei
Correct Answer: C
Rationale: The correct answer is C: 'Neutrons.' Isotopes are variants of an element that have the same number of protons and electrons but differ in the number of neutrons they contain. This difference in neutron count is what distinguishes isotopes from each other while maintaining the same chemical properties. Choice A, 'Electrons,' is incorrect because isotopes of the same element have the same number of electrons. Choice B, 'Protons,' is incorrect because isotopes of the same element have the same number of protons. Choice D, 'Nuclei,' is incorrect as nuclei refer to the central part of an atom containing protons and neutrons, and the question specifically asks about differences between isotopes of the same element.
Which of the following blood vessels contains the least oxygenated blood?
- A. Aorta
- B. Vena cava
- C. Pulmonary artery
- D. Femoral vein
Correct Answer: C
Rationale: The correct answer is C: Pulmonary artery. The pulmonary artery carries deoxygenated blood from the heart to the lungs for oxygenation. This blood is considered the least oxygenated in the body as it has just returned from circulating through the body's tissues and is in need of oxygen replenishment. Choice A, the aorta, is incorrect as it carries oxygenated blood from the heart to the rest of the body. Choice B, the vena cava, carries deoxygenated blood from the body back to the heart. Choice D, the femoral vein, also carries deoxygenated blood back to the heart from the lower extremities.