Skip to content
free
K
1
2
practice
Home
Math
English
Science
Social Studies
Contact
Language
English
Español
Sign In
/
High School Electives
/
Astronomy
/
Recombination, Dark Ages, and First Light
Grade Level
Astronomy
AST.254 Recombination, Dark Ages, and First Light
0%
Skill Level
🟢 Easy
00:00
Progress to Next Level
25% to Medium
Easy
Medium
Hard
Mastery
100%
Which option correctly names the source that helped reionize much of the early universe?
A
Microwaves released by the CMB alone
B
Reflected sunlight from newly formed planets
C
Ultraviolet radiation from the first stars and young galaxies
D
Sound waves traveling through empty space
Submit Answer