A botanist wants to determine if environmental temperature affects root growth. What is the independent variable in this study?
- A. Temperature
- B. Seedlings
- C. Light
- D. Root length
Correct Answer: A
Rationale: The correct answer is 'Temperature.' In an experiment, the independent variable is the factor that is deliberately manipulated or changed by the researcher. In this study, the botanist is specifically investigating how environmental temperature affects root growth, making temperature the independent variable. Choice B, 'Seedlings,' and Choice C, 'Light,' are not the independent variables in this context as they are not the factors being intentionally changed or manipulated. Choice D, 'Root length,' is the dependent variable, as it is the outcome that is being measured or observed in response to the changes in the independent variable, temperature.
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Which type of joint connects the bones of the skull?
- A. Synovial
- B. Fibrous
- C. Cartilaginous
- D. Ball-and-socket
Correct Answer: B
Rationale: Fibrous joints connect the bones of the skull. These joints are immovable or provide very limited movement, providing stability and protection to the brain. Synovial joints (Choice A) are found in the limbs and allow for a wide range of movements. Cartilaginous joints (Choice C) are connected by cartilage and allow limited movement. Ball-and-socket joints (Choice D) allow for a wide range of motion, such as the hip and shoulder joints, but they do not connect the bones of the skull.
What is the primary function of the respiratory system?
- A. To digest food
- B. To transport nutrients
- C. To exchange gases
- D. To regulate body temperature
Correct Answer: C
Rationale: The correct answer is C: To exchange gases. The primary function of the respiratory system is to facilitate the exchange of gases, specifically oxygen and carbon dioxide, between the body and the environment. This process is essential for cellular respiration, where oxygen is taken in and carbon dioxide is removed. Choices A, B, and D are incorrect. Digesting food is primarily the function of the digestive system, transporting nutrients is the role of the circulatory system, and regulating body temperature is primarily managed by the integumentary system and the nervous system, not the respiratory system.
DNA has both a 'sense' and 'antisense' strand. What is true about the antisense strand?
- A. It runs 5' to 3'.
- B. It runs 3' to 5'.
- C. It is used in replication.
- D. It is the direction DNA is stored.
Correct Answer: B
Rationale: The correct answer is B: 'It runs 3' to 5'. The antisense strand runs in the 3' to 5' direction, complementing the sense strand. Choice A is incorrect as the antisense strand runs in the opposite direction, which is 3' to 5'. Choice C is incorrect because the antisense strand is not directly involved in replication. Choice D is incorrect as the direction DNA is stored is not determined by the antisense strand.
Where is keratin found?
- A. It is a protein-digesting enzyme released by the stomach.
- B. It is released in the neuromuscular junction.
- C. It is a protein found in the hypodermis.
- D. It is a protein found in hair.
Correct Answer: D
Rationale: Keratin is a structural protein found in hair, skin, and nails, providing strength and protection. It forms the main structural component of hair, making choice D the correct answer. Choices A, B, and C are incorrect because keratin is not an enzyme released by the stomach, not released in the neuromuscular junction, and not found in the hypodermis. Remember that keratin is primarily associated with structural support in epithelial cells.
Which of the following factors does not strengthen a scientific argument?
- A. Lack of bias
- B. Extensive use of qualitative research and data
- C. Able to be reproduced and repeated by others
- D. Withstands the test of time
Correct Answer: B
Rationale: The correct answer is B. While qualitative data can provide valuable insights, it does not inherently strengthen a scientific argument to the same extent as quantitative data. Quantitative data is generally more precise, measurable, and easier to verify, making it a stronger basis for scientific arguments. Choices A, C, and D all contribute to strengthening a scientific argument. Lack of bias ensures objectivity and reliability, reproducibility by others validates the findings, and standing the test of time indicates the enduring validity and reliability of the argument.