1 Drainage basin-the area of land drained by a river. 2  Catchment area-the area within the drainage basin. 3  Watershed-the edge of highland surrounding a drainage basin.4  It marks the boundary between two drainage basins. 5  Source-The beginning or start of a river. 6  Confluence-the point at which two rivers or streams join. Watershed-the edge of highland surrounding a drainage basin. 2  It marks the boundary between two drainage basins. 3  Source-The beginning or start of a river. 4  Confluence-the point at which two rivers or streams join.
Dangerous levels of radiation in space could bar astronauts from a mission to Mars and limit prolonged activity on the moon, experts now caution.However, more research could reveal ways to handle the risks that radiation poses to space missions.The magnetic field of Earth protects humanity from radiation in space that can damage or kill cells. Once beyond this shield, people become far more vulnerable.owever, more research could reveal ways to handle the risks that radiation poses to space missions. The magnetic field of Earth protects humanity from radiation in space that can damage or kill cells. Once beyond this shield, people become far more vulnerable.
Risk factors. Each year millions of international travelers experience traveler's diarrhea. High-risk destinations for traveler's diarrhea include many areas of Central and South America, Mexico, Africa, the Middle East and most of Asia. Traveling to Eastern Europe and a few Caribbean islands also poses some risk.owever, your risk of traveler's diarrhea is generally low in Northern and Western Europe, Japan, Canada, Australia, New Zealand and the United States. Your chances of getting traveler's diarrhea are mostly determined by your destination. But certain groups of people have a greater risk of developing the condition.