Stars Are Formed from Interstellar Matter

question 105

Multiple Choice

Stars are formed from interstellar matter. Why then are stars in open clusters metal-rich, while stars in globular clusters are metal-poor?

• A) Open clusters contain very hot stars that produce metals by nuclear reactions in their outer layers.
• B) Globular clusters have "burned" their heavy elements over their longer lifetime.
• C) Globular clusters are too young for their stars to have produced any significant amount of metals.
• D) Open clusters are young, and stars have formed from material that has been enriched in metals by supernova explosions of previous stars.

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Definitions:

ST Segments

Portions of the electrocardiogram that reflect a period between the heart's contraction and the beginning of its recharge for the next beat.

Arrhythmia

An irregularity in the heart rate or rhythm, which can be too fast, too slow, or erratic, affecting the heart's ability to effectively pump blood.

Electrodes

Conductive materials that allow the flow of electric current in and out of devices such as batteries or sensors.

Dysrhythmia

An abnormality in a physiological rhythm, particularly in the pattern of electrical activity of the heart.