1. How did dark matter affect the development of structures in the early universe? It seeded the development of galaxies.
It seeded the development of quasare
It cooled pockets of gas to form nebulae.
it became part of black holes

2. How has scientific understanding about the composition of the universe changed over time? Select the two correct answers.
The percentage of dark matter has shrunk in scientists' estimates since the 1980s
The percentage of unknown material has grown in scientists' estimates since the 1970%
The percentage of ordinary matter has grown in scientists' estimates.
The percentage of dark energy has shrunk in scientists estimates

3. Which is evidence for the existence of dark energy?
Pulsars that seem to be moving closer at an accelerating rate.
Supernovae that are moving away at an accelerating rate.
Black holes that are expanding at a constant rate.
Galaxies that are rotating at a constant rate.