Table 1. Summary of analysis of five textbooks

Standard\Tb	Vs	Mn	Cj	Ks	Kh
Descriptive mechanism sequences	Walker circulation→Southern Oscillation→El Niño–La Niña →ENSO	El Niño–La Niña→Walker circulation→Southern Oscillation→ENSO	El Niño–La Niña→Southern Oscillation→ENSO	El Niño–La Niña→Southern Oscillation	El Niño–La Niña→Southern Oscillation→Walker Circulation→ENSO
ENSO impacts	Indirectly presented through Fig. 2	Not presented	Presented through Fig. 8	Partly presented through inquiry activity	Partly presented through the concept of “teleconnection”
Inquiry activities	Surface-level inquiry and minimal digital engagement through data collection and interpretation.	Partial extension of inquiry through prediction and reasoning with limited digital integration.	Basic information gathering with restricted inquiry development and digital literacy.	Applied inquiry through real- world cases with limited descriptive digital analysis.	Multidimensional inquiry linking science and economics with basic digital practices.

Vs, Visang education; Mn, MiraeN; Cj, Chunjae education; Ks, Kumsung; Kh, Kyohaksa; ENSO, El Niño-Southern Oscillation.