Correct Answer: C

Rationale: The prodromal period is the interval between the early manifestations of the disease and the time when the overt clinical syndrome is evident. Most communicable diseases are contagious during this time. Identifying the prodromal stage is crucial for early intervention and preventing the spread of the disease. While the source and causative agent are important aspects of disease control, recognizing the early signs in the prodromal stage allows the nurse to take timely actions. Constitutional symptoms occur during the active disease phase, indicating that the child has already been contagious, and early intervention opportunities may have passed.

Correct Answer: D

Rationale: In newborns, intramuscular vitamin K is traditionally administered into the vastus lateralis muscle. This site is preferred due to its large muscle mass and accessibility. The dorsogluteal site is not recommended for newborns due to the risk of injury to the sciatic nerve. The deltoid site is also not recommended for newborns. The rectus femoris muscle is not commonly used for intramuscular injections in newborns.

Correct Answer: D

Rationale: A heavy roundworm infection can cause anemia, anorexia, irritability, and an enlarged abdomen due to the worms' effects on nutrient absorption and intestinal function.

Correct Answer: A

Rationale: Thumb sucking is a normal self-soothing behavior in infants and usually does not indicate a problem. Reassuring the mother that this is normal is the appropriate response.

Correct Answer: A

Rationale: Playing peek-a-boo is an ideal play activity for a 7-month-old as it encourages visual tracking and social interaction, which are key developmental milestones at this age.