Nokea
In which group of the periodic table are alkali metals located?
- A. Group 1
- B. Group 2
- C. Group 7
- D. Group 8
Correct Answer: A
Rationale: Alkali metals, such as lithium, sodium, and potassium, are located in Group 1 of the periodic table. This group is known for its highly reactive properties, low melting points, and the tendency to form alkaline solutions when they react with water. Group 2 consists of alkaline earth metals and not alkali metals, making choice B incorrect. Group 7 includes halogens, while Group 8 includes noble gases. These groups do not contain alkali metals, so choices C and D are also incorrect. Therefore, the correct answer is Group 1.
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Which of the following is an example of a fibrous protein?
- A. Insulin
- B. Keratin
- C. Hemoglobin
- D. Collagen
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.
Which organ in the body is responsible for maintaining electrolyte balance and filtering waste from the blood?
- A. Liver
- B. Kidneys
- C. Heart
- D. Lungs
Correct Answer: B
Rationale: The correct answer is B: Kidneys. The kidneys are responsible for filtering waste from the blood and maintaining electrolyte balance. They help regulate the body's fluid levels and produce urine as a means of waste elimination. The liver primarily plays a role in detoxification and metabolism, not in maintaining electrolyte balance or filtering waste from the blood. The heart is responsible for pumping blood, not for electrolyte balance or waste filtration. The lungs are primarily involved in gas exchange, not in maintaining electrolyte balance or filtering waste from the blood.
What are the finger-like projections that increase the surface area for absorption in the small intestine called?
- A. Crypts of Lieberk¼hn
- B. Goblet cells
- C. Villi
- D. Paneth cells
Correct Answer: C
Rationale: A) Crypts of Lieberk¼hn are small pits in the lining of the small intestine that contain cells involved in the production of intestinal juices, but they do not increase the surface area for absorption.
B) Goblet cells are specialized cells that secrete mucus to protect the lining of the digestive tract, but they do not increase the surface area for absorption.
C) Villi are finger-like projections in the small intestine that increase the surface area available for nutrient absorption. Each villus contains blood vessels and lacteals (lymphatic vessels) that help absorb nutrients from digested food.
D) Paneth cells are specialized cells found in the small intestine that secrete antimicrobial substances, but they do not increase the surface area for absorption.
What is the acceleration due to gravity near the Earth's surface?
- A. 9.8 meters per second squared (m/s²)
- B. 6.3 meters per second squared (m/s²)
- C. 5.0 meters per second squared (m/s²)
- D. 12.5 meters per second squared (m/s²)
Correct Answer: A
Rationale: The acceleration due to gravity near the Earth's surface is approximately 9.8 m/s². This value is commonly used in physics calculations and represents the rate at which an object accelerates towards the Earth when in free fall. The acceleration due to gravity is a constant value near the Earth's surface and affects the motion of all objects. Choices B, C, and D are incorrect as they do not represent the standard value of 9.8 m/s². Understanding the correct value of acceleration due to gravity is fundamental in physics as it helps in solving various problems related to motion, forces, and energy.
Which structure in the respiratory system is responsible for gas exchange?
- A. Trachea
- B. Alveoli
- C. Bronchi
- D. Diaphragm
Correct Answer: B
Rationale: The alveoli in the lungs are responsible for gas exchange. Alveoli have a rich blood supply and thin walls, enabling the exchange of oxygen and carbon dioxide. Oxygen diffuses into the blood from the alveoli, while carbon dioxide diffuses out. The trachea functions as an air passage, bronchi are the main airways into the lungs, and the diaphragm is the primary muscle involved in breathing by aiding in lung expansion and contraction, but they are not directly responsible for gas exchange like the alveoli.