Final answer:
The air in the underwater Cosquer Cave entered through an underground passage. Henri Cosquer initially thought others had found his secret cave because of the human-like evidence inside, but he actually discovered prehistoric paintings and artifacts indicating ancient human activity.
Step-by-step explanation:
The Cosquer Cave, discovered by Henri Cosquer, is a prehistoric painted cave located underwater near Marseille, France. The cave's discovery sheds light on prehistoric art and the lives of people living during that era. Access to the cave suggests that air got into the underwater cave through an underground passage, which has changed over time due to rising sea levels since the cave's original use. When Cosquer first found the cave, he suspected others had been there because of evidence of human activity, like footprints. Upon further investigation, he found not modern intruders but ancient artifacts and majestic wall paintings dating back thousands of years, indicating that the cave had been visited and used by humans during the Upper Paleolithic period.
These ancient humans used materials like charcoal and ochre or haematite (iron oxide) to create intricate paintings. The artists of the Cosquer Cave skillfully incorporated the cave's natural contours into their work, giving their subjects a more three-dimensional and life-like appearance. The cave paintings not only provide insights into the artistic methods and cultural practices of prehistoric peoples but also provoke questions about their reasons for creating this art, whether for storytelling, religious purposes, or aesthetic expression.