Spiral Structure Can Be Triggered in a Disk Galaxy By

question 29

Multiple Choice

Spiral structure can be triggered in a disk galaxy by:

• A) the merger of close binary stars
• B) a supernova explosion
• C) the presence of an active nucleus
• D) the gravity of distant galaxies
• E) any disturbance to the disk

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Definitions:

Shaping Procedure

A method of training by which successive approximations toward a target behavior are reinforced.

Electroconvulsive Therapy

A psychiatric treatment in which seizures are electrically induced in patients to relieve severe mental disorders.

Systematic Desensitization

A technique used in behavior therapy to treat phobias and other behavior problems involving anxiety, by gradually exposing the patient to the anxiety-producing stimulus in a controlled environment.

Closed Places

Spaces or environments that are physically restricted, enclosed, or not open to the surrounding area or the public.