Answer:
D.) both a and c
Step-by-step explanation:
Past observations made early in history as well as telescopes and space probes are very important in studying our universe and galaxies.
- Space probes are increasingly gaining momentum as technological and scientific advancements are being made.
- Telescopes are used to see or picture objects that are very far away in space.
- Also, understanding the past records and historical data is essential for the study of the universe.
Microscopes are not used in galactic studies. They are only used to study the world of micro-organisms.