How to Merge Specific Paragraphs in Google Docs Using Apps Script

function mergeExplanationParagraphs() {
  var document = DocumentApp.getActiveDocument();
  var body = document.getBody();
  var totalElements = body.getNumChildren();

  // Iterate through the document elements in reverse order
  for (var i = totalElements - 1; i >= 0; i--) {
    var element = body.getChild(i);
    if (element.getType() === DocumentApp.ElementType.PARAGRAPH) {
      var text = element.getText().trim();
      if (text === "Explanation:") {
        if (i + 1 < totalElements) {
          var nextElement = body.getChild(i + 1);
          if (nextElement.getType() === DocumentApp.ElementType.PARAGRAPH) {
            var nextText = nextElement.getText();
            body.removeChild(element);
            nextElement.setText("Explanation: " + nextText);
          }
        }
      }
    }
  }
}