Biopsy material of oral mucosa demonstrates morphological signs of gums. What structural characteristics of the gingival mucosa can normally be observed?

Answer options

1. Tightly attached to the periosteum, lamina propria forms tall papillae, no muscular layer
2. No lamina propria or muscular layer
3. No muscular layer, well developed submucous layer
4. Loosely attached to the periosteum, well-defined muscular layer
5. Contains numerous small salivary glands