A Planetary Nebula Is Produced by

question 31

Multiple Choice

A planetary nebula is produced by

• A)A supernova explosion
• B)The dust left over when a cluster of stars forms
• C)The gradual loss of its outer layers by a dying star
• D)A nova explosion

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Definitions:

Placebo

An inert or non-therapeutic substance given to a control group in clinical trials to assess the psychological impact of receiving a treatment.

Natural

Naturally occurring and not manufactured or created by human beings.

Biased

Showing an unfair preference or prejudice for or against something or someone.

Internal Validity

The extent to which a study can demonstrate a cause-and-effect relationship between its variables.