It Is More Difficult to Determine the Total Amount of Dark

question 45

Multiple Choice

It is more difficult to determine the total amount of dark matter in an elliptical galaxy than in a spiral galaxy. Why?

• A) Elliptical galaxies lack the atomic hydrogen gas that we use to determine orbital speeds at great distances from the centers of spiral galaxies.
• B) Elliptical galaxies contain much less dark matter than spiral galaxies, so it's much more difficult to measure.
• C) Stars in elliptical galaxies are dimmer, making them harder to study.
• D) We cannot observe spectral lines for elliptical galaxies.

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Definitions:

Tracheal Tubes

A network of air tubes in insects that branch throughout the body for gas exchange.

Spiracles

External respiratory openings in insects and some amphibians and fish, used for breathing.

Organismic Respiration

The process by which living organisms take in oxygen and release carbon dioxide, essential for energy production.

Citric Acid Cycle

A succession of chemical processes that all oxygen-requiring organisms utilize to produce energy, achieved through the oxidation of acetate extracted from carbohydrates, fats, and proteins.