Which of the following is a pure substance? a) salt water b) carbon dioxide c) air d) soda

Which statement best describes the nature of science? a. science discoveries using the latest technology are the most valuable. b. scientific theories and laws are based on beliefs and popular opinion. c. scientific ideas change over time as new information is discovered. d. science is superior to other fields such as art, philosophy, and music. i think its c

What is involved in redox reactions

20 point pls brianliest 1. what does a red shift mean? blue shift? 2. describe the big bang theory. according to this theory, how old is the universe? 3. scientists believe the universe is expanding. what is the evidence that supports this? 4. describe a nebula. 5. describe the 3 types of galaxies. what is a barred spiral galaxy? 6. what is a light year? how far is alpha centauri from earth? 7. describe the universal law of gravitation. be sure to include gravitational force between two objects. 8. describe the planets’ orbits around the sun. 9. what is the asteroid belt? where is it located? 10. describe rotation and revolution of earth. what determines an earth day and year? 11. how do galaxies exist? 12. compare and contrast the inner and outer planets. 13. what causes the seasons?