Francis is conducting an experiment to determine whether the acidity of ocean water affects the growth of ocean plants. he has 10 aquariums, each containing the same species of ocean plant. one has a ph of 8.2, the approximate ph of the ocean. the others vary in acidity from 0 to 14. francis measures the growth of each plant after one month. each aquarium is kept at the same temperature and receives the same amount of sunlight. what is the variable being tested in this experiment? acidity or ph species of plant temperature amount of sunlight

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?