Which statement best defines a universal law?
a: it is in effect at all times.
b: it changes over time.
c: it operates only under specific conditions
d : it is in effect some of the time

What are the responsibilities of the region of the brain highlighted below? =+= will rate brainiest =+=

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?

Our planet has experienced five major extinctions in the four billion year history of life. the first, 450 million years ago, occurred shortly after the evolution of the first land-based plants and 100 million years after the cambrian explosion. the second extinction occurred 350 million years ago, causing the formation of coal forests. next earth experienced two mass extinctions during the triassic period, between 250 and 200 million years ago. the fifth mass extinction occurred 65 million years ago, ending the reptilian dominance of the earth. according to richard leakey, the sixth mass extinction is happening right now. leakey suggests that we, the human race, are the cause. each year, at our hand, approximately 50,000 species vanish from earth. he believes that man is destroying earth at a rate comparable with the impact of a giant asteroid. leakey's statistics indicate that 50% of earth's species will become extinct within the next 100 years assuming leakey's hypothesis of a sixth mass extinction to be true, how will we expect the model to change? a) a sharp spike in the graph approximately 100 million years from now b) a dip in the graph, followed by a sharp spike about 100 million years from now c) a sharp spike in the graph immediately following the "0" location of the x axis d) a plateau following the "0" mark on the x axis, followed by a gradual rise to a new peak