Cells obtain energy by either capturing light energy through photosynthesis or by breaking down carbohydrates through cellular respiration. In both photosynthesis and cellular respiration, the energy is ultimately derived from the Sun in a A.
reversible process.
B.
highly efficient process which involves no loss of heat to the environment.
C.
one-way process.
D.
pathway that involves taking in heat from the environment at each step.

80 points pls brainliest 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?