Which of the following best defines a gene pool? A. the sum of all genetic traits in a population’s individuals at a given time
B. any movement of genes from one population to another
C. any movement of organisms from one environment to another
D. the random change in the frequency of an allele in a pop

I need answer quick please

What is the next step in the process after a substrate enters the active site of an enzyme

Me 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?

What type of reaction is photosynthesis