Roughly What Percentage of the Total Mass of a Galaxy

question 59

Multiple Choice

Roughly what percentage of the total mass of a galaxy is made up of luminous, or normal, matter?

• A) 5 percent
• B) 25 percent
• C) 33 percent
• D) 50 percent
• E) 90 percent

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Definitions:

Seminal Fluid

A fluid that is secreted by the male reproductive organs and contains sperm cells, which are necessary for fertilization.

Prefrontal Cortex

The area of the cortex at the very front of the brain that specializes in anticipation, planning, and impulse control.

Cognitive Control

The mental ability to regulate and manipulate one's own cognitive processes, such as focusing attention, controlling impulses, and planning.

Sexual Maturation

The process by which individuals reach a state of full reproductive ability.