What Observations Suggest the Mass of the Galaxy Goes Much

question 3

Multiple Choice

What observations suggest the mass of the Galaxy goes much farther out than its visible disc?

• A) the rotation curve of the outermost portions of the disc
• B) infrared observations of distant brown dwarfs
• C) the orbits of the open clusters in the disc
• D) 21- cm maps of the spiral arms
• E) X- ray images of other galaxies' discs from Chandra

---

Definitions:

Development Periods

Distinct phases in the lifespan characterized by unique physical, psychological, or cognitive changes, such as infancy, childhood, adolescence, and adulthood.

Adolescence

The interval of development characterized by psychological and physical transitions, spanning from puberty to the legal age of adulthood.

Middle Childhood

Refers to the developmental stage ranging from approximately six to twelve years of age, marked by significant growth in cognitive, social, and emotional areas.

Biological Processes

Changes in an individual’s body.