The Best Explanation for the Activity at the Center of the Galaxy

question 4

Multiple Choice

The best explanation for the activity at the center of the galaxy is a(n) ____.

• A) supercluster of O and B stars
• B) black hole with a mass several thousand times the Sun's
• C) giant atomic hydrogen cloud energized into a single, massive emission nebula
• D) black hole with a mass several million times the Sun's
• E) exotic object known as a "magnetar"

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Definitions:

Cholesterol Ratios

A way to assess cardiovascular risk by comparing the levels of different types of cholesterol in the blood.

HDL

High-density lipoprotein, often referred to as "good" cholesterol, which helps remove other forms of cholesterol from the bloodstream.

LDL

Low-Density Lipoprotein, often referred to as "bad" cholesterol, which can accumulate in the walls of blood vessels and lead to heart diseases.

Osteoporosis

A medical condition characterized by weakened bones, making them fragile and more prone to fractures.