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What is the unit of measurement for density?
- A. Grams per liter (g/L)
- B. Kilograms per cubic meter (kg/m³)
- C. Pounds per square inch (psi)
- D. Newtons per meter (N/m)
Correct Answer: A
Rationale: Density is defined as mass per unit volume. The most commonly used unit for density in the metric system is grams per liter (g/L). Kilograms per cubic meter (kg/m³) is also a common unit for density, but grams per liter is more frequently used in everyday measurements. Pounds per square inch (psi) is a unit of pressure, not density. Newtons per meter (N/m) is a unit of force per unit length, not density.
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What is the primary function of the lymphatic system?
- A. To transport oxygen throughout the body
- B. To filter blood and remove waste
- C. To fight infection and remove excess fluid
- D. To transport hormones
Correct Answer: C
Rationale: The correct answer is C: 'To fight infection and remove excess fluid.' The lymphatic system plays a crucial role in the body's immune response by fighting infections through lymphocytes and removing excess fluid from tissues, maintaining fluid balance. It does not primarily transport oxygen, filter blood, or transport hormones. While the lymphatic system is involved in lipid absorption and transport, its primary functions are related to immunity and fluid balance.
During a scientific investigation, what is intentionally changed or manipulated?
- A. The dependent variable.
- B. The control.
- C. The hypothesis.
- D. The independent variable.
Correct Answer: D
Rationale: During a scientific investigation, the independent variable is intentionally changed or manipulated by the researcher to observe its impact or effect on the dependent variable. The independent variable is the one being tested or studied to see how it influences the dependent variable. In contrast, the dependent variable is the outcome or response that is measured in an experiment and is expected to change as a result of the manipulation of the independent variable. Choices A, B, and C are not directly altered during a scientific investigation but play different roles in the research process. Therefore, the correct answer is D - the independent variable.
Which element is used in jewelry due to its malleability and resistance to tarnish?
- A. Iron
- B. Copper
- C. Gold
- D. Silver
Correct Answer: C
Rationale: Gold is the correct answer. Gold is a popular choice for jewelry due to its exceptional malleability, allowing it to be easily shaped into intricate designs. Moreover, gold is resistant to tarnish, ensuring the jewelry retains its beauty over time. Iron is not commonly used in jewelry due to its susceptibility to rusting. Copper is also not as popular in jewelry making as gold due to its tendency to tarnish and cause skin discoloration. While silver is used in jewelry, it is more prone to tarnish compared to gold, making it less ideal for long-lasting pieces.
Which property of matter refers to the amount of space occupied by an object and is measured in cubic units?
- A. Mass
- B. Density
- C. Weight
- D. Volume
Correct Answer: D
Rationale: Volume is the property of matter that refers to the amount of space occupied by an object. It is measured in cubic units, such as cubic meters or cubic centimeters. Mass, on the other hand, is the amount of matter in an object, weight is the force of gravity acting on an object, and density is the mass per unit volume of a substance. In this question, the key concept is the space occupied by an object, which directly relates to volume, making it the correct answer. Choices A, B, and C are incorrect as they do not specifically pertain to the amount of space occupied by an object.
What is the building block of DNA?
- A. Amino acid
- B. Nucleotide
- C. Phosphate group
- D. Fatty acid
Correct Answer: B
Rationale: - Amino acids are the building blocks of proteins, not DNA.
- Nucleotide is the correct building block of DNA. A nucleotide consists of a sugar (deoxyribose in DNA), a phosphate group, and a nitrogenous base (adenine, thymine, cytosine, or guanine).
- The option 'C) Phosphate group' is incorrect as it is only part of a nucleotide, not the complete building block of DNA.
- Fatty acids are not the building blocks of DNA; they are a type of lipid molecule.