Answer:all the things that you keep the same in the experiment
Explanation:
The “R” Horizon would be 5
<span> RNA was thought of as little more than a messenger between DNA and proteins, carrying instructions as messenger RNA (mRNA) to build proteins. However, RNA can do far more. It can drive chemical reactions, like proteins, and carries genetic information, like DNA. And because RNA can do both these jobs, most scientists think life as we know it began in an RNA world, without DNA and proteins.</span>
b. the burning of fossil fuels for energy and transportation
