Here are paraphrases of the passages:
1. In an interview, Jacques Cousteau explained that Antarctica plays a key role in regulating the Earth's climate similar to the sun's role in providing heat. Cold water from Antarctica circulates and mixes with warmer tropical waters, helping to cool surface temperatures and the atmosphere. However, human activities now threaten the fragility of this climate regulating system.
2. Most bicycling fatalities, which number over 1,000 annually, result from head injuries. Young children make up half of bicycle deaths. One study found that wearing a bicycle helmet can decrease the risk of head injury by 85% during an accident by absorbing shock and cushioning the head.