Alvin is studying a model of the chemical structure of a common nucleic acid. He observes that the nucleic acid consists of four nitrogenous

bases: adenine (A), cytosine (C), guanine (G), and uracil (U).

Alvin's observation most strongly supports which of these conclusions?

A. The nucleic acid is a form of RNA, and is not DNA.

B. The nucleic acid is either mRNA or rRNA, but not tRNA.

C. The nucleic acid is either RNA or DNA.

D. The nucleic acid is DNA, and is not RNA.

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?