Nokea
Which of the following best describes the statement: 'This flower is dead; someone must have forgotten to water it'?
- A. A classification
- B. An observation
- C. An inference
- D. A collection
Correct Answer: C
Rationale: The correct answer is C - 'An inference'. An inference is a conclusion drawn based on evidence and reasoning, not directly observed facts. In this statement, the conclusion that someone must have forgotten to water the flower is inferred from the observed fact that the flower is dead. Choice A - 'A classification' is incorrect because the statement does not categorize or classify the flower in any way. Choice B - 'An observation' is incorrect because it does not involve interpreting or drawing a conclusion from the observed fact. Choice D - 'A collection' is incorrect as it does not relate to the process of drawing a conclusion based on evidence.
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What is the role of hemoglobin in the human body?
- A. Transport oxygen in red blood cells
- B. Bind oxygen to red blood cells
- C. Carry carbon dioxide from tissues to lungs
- D. Help red blood cells transport oxygen
Correct Answer: D
Rationale: The correct answer is D: 'Help red blood cells transport oxygen.' Hemoglobin acts as a carrier molecule in red blood cells, binding to oxygen in the lungs and releasing it in the tissues. It facilitates the transport of oxygen from the lungs to the tissues and aids in returning carbon dioxide from the tissues to the lungs. Choices A, B, and C are incorrect because hemoglobin itself does not transport oxygen independently or bind oxygen to red blood cells nor does it carry carbon dioxide from tissues to lungs; instead, it assists red blood cells in the transportation of oxygen.
What type of bond is formed when electrons are transferred between atoms?
- A. Transfer bond
- B. Static bond
- C. Covalent bond
- D. Ionic bond
Correct Answer: D
Rationale: The correct answer is 'D: Ionic bond.' An ionic bond is formed when electrons are transferred between atoms. In an ionic bond, one atom donates electrons to another atom, resulting in the formation of positively and negatively charged ions that are attracted to each other, creating a strong bond. Choice A, 'Transfer bond,' is incorrect because there is no common term known as a 'Transfer bond' in chemistry. Choice B, 'Static bond,' is incorrect as it does not describe the process of electron transfer between atoms. Choice C, 'Covalent bond,' is incorrect because in a covalent bond, electrons are shared between atoms rather than transferred outright, making it different from an ionic bond.
How many grams of solid CaCO3 are needed to make 600 mL of a 0.35 M solution? The atomic masses for the elements are as follows: Ca = 40.07 g/mol; C = 12.01 g/mol; O = 15.99 g/mol.
- A. 18.3 g
- B. 19.7 g
- C. 21.0 g
- D. 24.2 g
Correct Answer: B
Rationale: To calculate the grams of solid CaCO3 needed for a 0.35 M solution, we first find the molar mass of CaCO3: Ca = 40.07 g/mol, C = 12.01 g/mol, O = 15.99 g/mol. The molar mass of CaCO3 is 40.07 + 12.01 + (3 * 15.99) = 100.08 g/mol. The molarity formula is Molarity (M) = moles of solute / liters of solution. Since we have 0.35 moles/L and 600 mL = 0.6 L, we have 0.35 mol/L * 0.6 L = 0.21 moles of CaCO3 needed. Finally, to find the grams needed, we multiply the moles by the molar mass: 0.21 moles * 100.08 g/mol = 21.01 g, which rounds to 19.7 g. Therefore, 19.7 grams of solid CaCO3 are needed to make 600 mL of a 0.35 M solution. Choice A (18.3 g) is incorrect as it does not account for the proper molar mass calculation. Choice C (21.0 g) and Choice D (24.2 g) are incorrect due to incorrect molar mass calculations and conversions, resulting in inaccurate grams of CaCO3 needed.
Which blood component is responsible for the production of antibodies?
- A. Platelets
- B. Red blood cells
- C. White blood cells
- D. Plasma cells
Correct Answer: C
Rationale: White blood cells, specifically B lymphocytes or B cells, are responsible for producing antibodies as part of the immune response. When the body encounters foreign substances (antigens), B cells are activated to differentiate into plasma cells, which then produce antibodies to target and neutralize the antigens. Platelets are involved in blood clotting and not in antibody production. Red blood cells are primarily responsible for carrying oxygen in the blood and do not produce antibodies. Plasma cells are actually differentiated B cells that produce antibodies, but the question asks for the blood component responsible for the production of antibodies, which is the white blood cells.
Which system is responsible for transporting nutrients, gases, and wastes in the body?
- A. Respiratory system
- B. Digestive system
- C. Circulatory system
- D. Nervous system
Correct Answer: C
Rationale: The circulatory system is responsible for transporting nutrients, gases, and wastes to and from the cells in the body. It includes the heart, blood vessels, and blood, which work together to distribute oxygen, nutrients, and remove waste products throughout the body. The respiratory system is primarily involved in gas exchange, the digestive system breaks down food for absorption, and the nervous system is responsible for transmitting signals throughout the body.