what do astronomers need to observe stars?
at least two lenses the sun isolating and copying genes scales or plates physical properties outer space hydrogen and oxygen rocket ships
A B C D E F G H
what do astronomers need to observe stars? (A) at least two lenses (B) the sun (C) isolating and copying genes (D) scales or plates (E) physical properties (F) outer space (G) hydrogen and oxygen (H) rocket ships