Nokea
Which of the following best describes one of the roles of RNA?
- A. Manufacturing the proteins needed from DNA
- B. Creating the bonds between the elements that make up DNA
- C. Sending messages about the correct sequence of proteins in DNA
- D. Forming the identifiable double helix shape of DNA
Correct Answer: C
Rationale: The correct answer is C. RNA serves as a messenger that carries instructions from DNA for protein synthesis. It does not manufacture proteins directly from DNA (choice A), create bonds within DNA (choice B), or form the double helix structure of DNA (choice D). Therefore, the primary role of RNA is to convey information about the correct sequence of proteins to be synthesized based on the DNA sequences it receives.
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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.
Which of the following is a constant?
- A. The number of protons in an oxygen atom
- B. The temperature at which iron ore will melt
- C. The human population size
- D. The time the sun rises each day
Correct Answer: A
Rationale: The number of protons in an oxygen atom is a constant. This value is determined by the atomic number of the element and does not change regardless of the isotope of oxygen. The number of protons defines the element and remains consistent under normal conditions. Choices B, C, and D are not constants. The temperature at which iron ore will melt can vary depending on factors like pressure, the human population size is constantly changing, and the time the sun rises each day varies with the seasons and location.
Which blood vessel carries oxygenated blood back to the heart?
- A. Pulmonary vein
- B. Pulmonary artery
- C. Aorta
- D. Superior vena cava
Correct Answer: A
Rationale: The corrected question is asking for a blood vessel that carries oxygenated blood back to the heart. The pulmonary vein is the correct choice as it carries oxygenated blood from the lungs back to the heart during systemic circulation. The pulmonary artery carries deoxygenated blood from the heart to the lungs for oxygenation. The aorta is the main artery that carries oxygenated blood away from the heart to the body. The superior vena cava returns deoxygenated blood from the upper body back to the heart.
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 is an example of the location and function of cartilage in the body?
- A. The dense connective tissue that makes up the majority of the structural skeleton
- B. The supportive pads that provide cushioning at joints, such as between the vertebrae of the spinal cord
- C. The connective structure made of fibrous collagen that connects muscles and bones
- D. The layer beneath the skin and on the outside of internal organs that provides cushioning and protection
Correct Answer: B
Rationale: Cartilage is a type of flexible connective tissue that acts as supportive pads providing cushioning at joints, like those found between the vertebrae of the spine. This specific function of cartilage helps in reducing friction and absorbing shock in these areas, contributing to joint flexibility and protection. Choices A, C, and D do not accurately describe the function and location of cartilage in the body. Option A incorrectly refers to dense connective tissue, which is different from cartilage. Option C describes tendons or ligaments, which are not cartilage. Option D refers to adipose tissue, which is a type of connective tissue that stores fat and provides insulation, but it is not cartilage.