65 million years ago there was a mass extinction that is best known for killing the dinosaurs. There was also a large deposit of dust that contained substances only found in asteroids. What most likely killed off the dinosaurs?

Explain why biological control methods are generally environmentally superior to chemical pest control methods.

What should be the strand of complementary dna produced by the strand of dna shown below cgt ata

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?