Correct Answer: D

Rationale: Having six teeth at 6 months is earlier than the typical tooth eruption schedule, but it is not unusual or dangerous. It is within the range of normal variations in infant development.

Correct Answer: B

Rationale: Roundworm (ascariasis) is typically transmitted through ingestion of contaminated soil, not directly from person to person. This statement indicates a misunderstanding requiring clarification.

Correct Answer: A

Rationale: The first sign of puberty in boys is typically the enlargement of the testes. This is due to the increase in production of testosterone, which leads to physical changes such as growth of the testes. Choice B, decreased levels of testosterone, is incorrect as puberty is marked by an increase in testosterone levels. Choice C, voice deepening, and choice D, pubic hair growth, usually occur later in the puberty process compared to testicular enlargement, making them incorrect answers.

Correct Answer: C

Rationale: Breastfed infants may need fluoride supplements starting at 6 months if they are not receiving fluoride from other sources, such as drinking water.

Correct Answer: D

Rationale: Intense perianal itching is the most common symptom of pinworm infection, especially at night when the female worms lay their eggs