Problem: Vacuum is useful in a variety of processes and devices. Its first widespread use was in the incandescent light bulb to protect the filament from chemical degradation. The chemical inertness produced by a vacuum is also useful for electron beam welding, cold welding, vacuum packing and vacuum frying. Ultra-high vacuum is used in the study of atomically clean substrates, as only a very good vacuum preserves atomic-scale clean surfaces for a reasonably long time (on the order of minutes to days). High to ultra-high vacuum removes the obstruction of air, allowing particle beams to deposit or remove materials without contamination. This is the principle behind chemical vapor deposition, physical vapor deposition, and dry etching which are essential to the fabrication of semiconductors and optical coatings, and to surface science. The reduction of convection provides the thermal insulation of thermos bottles. Deep vacuum lowers the boiling point of liquids and promotes low temperature outgassing which is used in freeze drying, adhesive preparation, distillation, metallurgy, and process purging. The electrical properties of vacuum make electron microscopes and vacuum tubes possible, including cathode ray tubes. The elimination of air friction is useful for flywheel energy storage and ultracentrifuges.
What is produced by a vacuum and used in electron beam welding and vacuum frying?
The answer is the following: chemical inertness

Problem: University education includes teaching, research, and social services activities, and it includes both the undergraduate level (sometimes referred to as tertiary education) and the graduate (or postgraduate) level (sometimes referred to as graduate school). Universities are generally composed of several colleges. In the United States, universities can be private and independent like Yale University; public and state-governed like the Pennsylvania State System of Higher Education; or independent but state-funded like the University of Virginia. A number of career specific courses are now available to students through the Internet.
What are usually Universities made up of?
The answer is the following: several colleges

Problem: Regulation of hunting within the United States dates from the 19th century. Some modern hunters see themselves as conservationists and sportsmen in the mode of Theodore Roosevelt and the Boone and Crockett Club. Local hunting clubs and national organizations provide hunter education and help protect the future of the sport by buying land for future hunting use. Some groups represent a specific hunting interest, such as Ducks Unlimited, Pheasants Forever, or the Delta Waterfowl Foundation. Many hunting groups also participate in lobbying the federal government and state government.
What organizations provide hunter education and help protect the future of the sport?
The answer is the following: Local hunting clubs and national organizations

Problem: Some predators take advantage of the concentration of birds during migration. Greater noctule bats feed on nocturnal migrating passerines. Some birds of prey specialize on migrating waders.
What do greater noctule bats feed on?
The answer is the following:
nocturnal migrating passerines