Answer:
Place a glowing splint in the test tube, and if it reignites, it could be oxygen. Place a burning splint into a test tube, and if it goes out, it could be carbon dioxide. Or, place carbon dioxide gas in limewater, and if it turns milky and gets chunks, it is carbon dioxide.
C scientific law is something that's always going to be true
Answer:
D) largest mass extinction event in Earth's history
Explanation:
The cambrian era started following the pre-cambrian extinction
