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Lithium has an atomic number of 3 and a mass number of 7. What is the number of protons in a lithium atom?
- A. 7
- B. 4
- C. 12
- D. 3
Correct Answer: D
Rationale: The number of protons in an atom is equal to its atomic number. In this case, lithium has an atomic number of 3, so it contains 3 protons. The mass number (7) includes both protons and neutrons, with the difference between the mass number and atomic number representing the number of neutrons. Therefore, the correct answer is 3 protons in a lithium atom.
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Testosterone is classified as which of the following types of hormones?
- A. Androgen
- B. Progestin
- C. Estrogen
- D. Aldosterone
Correct Answer: A
Rationale: Testosterone is classified as an androgen, which is a type of steroid hormone responsible for the development of male characteristics such as facial hair, deepening of the voice, and muscle growth. Androgens are primarily produced in the testes in males and in smaller amounts in the ovaries and adrenal glands in females. Progestins, estrogens, and aldosterone are different types of hormones with distinct functions and are not categorized under androgens.
A group of students performed an experiment to test terminal velocity, which is the greatest speed obtained by a falling object. The students dropped different numbers of coffee filters and measured the resulting terminal velocity. Which of the following conclusions is supported by the data in the following data table?
- A. The greater the number of filters, the smaller the terminal velocity.
- B. Heavier objects take more time to reach terminal velocity.
- C. Terminal Velocity is when the force of gravity is equal to air resistance.
- D. Heavier objects fall faster than lighter objects.
Correct Answer: D
Rationale: The correct conclusion supported by the data is that heavier objects fall faster than lighter objects. Heavier objects experience a greater gravitational force, causing them to fall faster. This aligns with the concept of terminal velocity, which is the maximum speed a falling object can reach when the force of gravity is balanced by air resistance. Due to the stronger pull of gravity on heavier objects, they can overcome air resistance more effectively and reach terminal velocity faster compared to lighter objects.
What is essential for new scientific findings to be published?
- A. To prevent other scientists from performing similar tests
- B. For other scientists to validate or disapprove of findings
- C. Publishing findings to help scientists become more biased
- D. Scientists being paid if their findings are published
Correct Answer: B
Rationale: For new scientific findings to be published, it is essential for other scientists to validate or disapprove of the findings. This validation process, known as peer review, ensures the credibility and reliability of the research. Peer review allows for critical evaluation, verification, and identification of any potential errors or biases in the study, thereby upholding the integrity and quality of scientific knowledge. Without this validation by peers, the scientific community cannot confidently accept the findings as accurate and trustworthy, making the peer review process a crucial step in the dissemination of scientific knowledge.
Through which structure does blood exit the glomerulus?
- A. Distal tubule
- B. Proximal tubule
- C. Afferent arteriole
- D. Efferent arteriole
Correct Answer: D
Rationale: The correct answer is D, the efferent arteriole. The efferent arteriole carries blood away from the glomerulus after filtration. Blood enters the glomerulus through the afferent arteriole for filtration. The proximal and distal tubules are involved in tubular reabsorption and secretion of substances after filtration occurs in the glomerulus. The efferent arteriole plays a crucial role in maintaining the proper flow of blood through the nephron and ensures that the filtered substances are carried away for further processing in the renal tubules.
Which of the following is used to determine a person's DNA sequence?
- A. hormones
- B. enzymes
- C. blood types
- D. genes
Correct Answer: D
Rationale: Genes are the correct choice for determining a person's DNA sequence. Genes carry genetic information that dictates various traits and characteristics in individuals. A person's unique DNA sequence is determined by the specific arrangement of nucleotides within their genes. Scientists can analyze genes to decode the DNA sequence that represents an individual's genetic composition.