Allopatric speciation requires which of the following? A. partial genetic isolation combined with natural selection B. introduction of two populations to each other, forming a hybrid zone C. extreme natural selection in a hostile environment D. total separation of two populations by a physical barrier

Describe at least 2 abiotic and two biotic factors found in the desert biome how do these abiotic factors interact with the biotic factors

Two critical interventions to turn around the opioid crises are:

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?