Water is the most naturally abundant and widely used extinguishing substance. It extinguishes fire by cooling. There are three main types of water deluge systems, components of which are shown below. From left to right, they are: fine water spray systems, sprinkler systems, and water spray systems.
Vitamin D, a steroid hormone that influences virtually every cell in your body and has been positively linked to health conditions ranging from cancer to heart disease, may significantly boost fertility in both men and women.
Health.com: Vitamin D -- why you need this vitamin now. Pregnant women need to take 4,000 IU of vitamin D a day, says Bruce Hollis, Ph.D., the director of pediatric nutritional sciences at the Medical University of South Carolina, in Charleston, and one of the authors of the study.