Over Time, What Is the Net Effect of the Star-

question 21

Multiple Choice

Over time, what is the net effect of the star- gas- star cycle in the Milky Way?

• A)The total mass in the galaxy's interstellar medium is gradually increased, and the new gas is continually enriched in heavy elements.
• B)The gas of the interstellar medium is continually depleted in elements heavier than helium.
• C)The temperature of the interstellar medium varies between the cool 10- 50 degrees (Kelvin)required to form stars and the 2000- 30,000 degree (Kelvin)temperatures of the outer layers of the stars that form. But over time, more and more of the interstellar medium remains cool.
• D)The total mass in the galaxy's interstellar medium is gradually reduced, and the remaining gas is continually enriched in heavy elements.
• E)There is no net effect to the cycle. Mass in the interstellar medium lost to star formation is exactly replaced by stellar winds and supernova explosions.

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Definitions:

Aldosterone

A hormone produced by the adrenal glands that helps regulate blood pressure by controlling sodium and potassium levels in the body.

Pituitary Gland

Pea-sized endocrine gland in the forebrain; interacts closely with the adjacent hypothalamus.

Antidiuretic Hormone

A hormone, also known as vasopressin, that regulates water balance in the body by reducing the volume of water excreted by the kidneys.

Luteinizing Hormone

A hormone produced by the anterior pituitary gland that plays a critical role in regulating the function of the ovaries and testes.