1. Which vitamin is essential for proper absorption of calcium and plays a role in lung function?

A. Vitamin A
B. Vitamin B12
C. Vitamin D
D. Vitamin E

Correct answer: C

Rationale: The correct answer is C, Vitamin D. Vitamin D is essential for the proper absorption of calcium in the intestines, which is crucial for maintaining strong bones and teeth. Additionally, Vitamin D plays a role in lung function by supporting respiratory health and reducing inflammation in the lungs. Vitamin A is important for vision and immune function, Vitamin B12 is necessary for red blood cell formation and neurological function, and Vitamin E is an antioxidant that helps protect cells from damage.

2. What are energy levels and orbitals?

A. Energy levels are the paths that electrons travel around the nucleus of an atom, and orbitals are the regions where electrons are most likely to be found.
B. Energy levels are the regions where electrons are most likely to be found, and orbitals are the paths that electrons travel around the nucleus of an atom.
C. Energy levels are the same as orbitals.
D. Energy levels and orbitals do not exist.

Correct answer: A

Rationale: Energy levels refer to the specific energies that electrons in an atom can have, while orbitals are the regions within an atom where electrons are most likely to be found. Electrons do not travel in fixed paths around the nucleus like planets around the sun, as suggested in option B. Option C is incorrect because energy levels and orbitals are distinct concepts in atomic structure. Option D is incorrect as energy levels and orbitals are fundamental concepts in understanding the behavior of electrons in atoms.

3. Which of the following is an example of stabilizing selection?

A. Selection that favors extreme traits in a population
B. Selection that removes individuals with extreme traits
C. Selection that maintains the current average trait in a population
D. Selection that favors one specific trait over all others

Correct answer: C

Rationale: Rationale: - Stabilizing selection is a type of natural selection that favors the intermediate variants in a population, while selecting against the extreme traits. This results in the maintenance of the current average trait in the population. - Option A is incorrect because stabilizing selection does not favor extreme traits; instead, it favors the average trait. - Option B is incorrect because stabilizing selection does not remove individuals with extreme traits; it acts against extreme traits by favoring the intermediate variants. - Option D is incorrect because stabilizing selection does not favor one specific trait over all others; it favors the average trait by selecting against extreme traits.

4. Aromatic compounds

A. Contain a ring structure with alternating single and double bonds
B. Readily undergo addition reactions
C. Are easily broken down by water
D. Do not contain any pi (Ï€) bonds

Correct answer: A

Rationale: The correct answer is A: 'Aromatic compounds contain a ring structure with alternating single and double bonds.' Aromatic compounds exhibit a special stability due to the delocalization of pi electrons within the ring, known as resonance. This resonance occurs because of the alternating single and double bonds in the ring structure, making them less reactive towards addition reactions compared to alkenes, which have only double bonds. This stability also makes aromatic compounds less likely to be easily broken down by water, as they are relatively inert in many chemical reactions. Therefore, aromatic compounds do contain pi (π) bonds due to the presence of the alternating single and double bonds in their ring structure.

5. Which word is most closely associated with the adjective "ambiguous"?

A. Precise
B. Vague
C. Definite
D. Straightforward

Correct answer: B

Rationale: "Ambiguous" implies uncertainty or multiple interpretations, making "vague" its closest synonym.

6. Which number is the opposite of -3?

A. -6
B. 3
C. 0
D. 6

Correct answer: B

Rationale: The opposite of a number is the one with the same distance from zero but on the opposite side of the number line. So, the opposite of -3 is 3.