1) hiv weakens the immune system by killing a. antibodies. c. t cells. b. b cells. d. killer t cells.

2 ) which of the following statements is false regarding an autoimmune disease?
a.
the body reacts with its own cells and tissues
c.
it can involve cell-mediated responses
b.
its mechanism is well understood
d.
it can involve humoral responses

When a human or animal consumes food, the carbon in that food is most likely to be converted into which of the following elements? a. carbon remains carbon b. nitrogen c. oxygen d. hydrogen

How does the carbon cycle involve an exchange of carbon

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?