Safety is the state of being "safe" (from French sauf), the condition of being protected from harm or other non-desirable outcomes. Safety can also refer to the control of recognized hazards in order to achieve an acceptable level of risk.
Science (from Latin scientia, meaning "knowledge") is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe.
Some people talk as if meeting the gaze of absolute goodness would be fun. They need to think again. They are still only playing with religion. Goodness is either the great safety or the great danger — according to the way you react to it.
Like all ecosystems on Earth supporting animal and plant life, aquatic ecosystems need oxygen. However, oxygen availability in these systems is threatened by global warming and excessive input of nutrients such as from agriculture and wastewaters, known as eutrophication.