Complex sentence: During deep dives, pinnipeds store the air expelled from their collapsed lung into their bronchioles and trachea, which prevents them from experiencing decompression sickness, oxygen toxicity and nitrogen narcosis.
Split into simpler sentences: During deep dives, pinnipeds store the air expelled from their collapsed lung into their bronchioles and trachea. This prevents them from experiencing decompression sickness, oxygen toxicity and nitrogen narcosis.