Since you provide no options, here are the usual parts of scientific method :
- Idea / question which answer you want to find out
- Research , collecting all kinds of data
- Hypothesis , an explanation that is made at the starting point, before the experiment
- Experiment , to find out whether your hypothesis is right
- Analyze the data that you got from the experiment
- Conclusion, your final judgement based on the result of your experiment
The nitrogenous bases form hydrogen bonds between opposing DNA strands to form the rungs of the "twisted ladder" or double helix of DNA or a biological catalyst that is found in the nucleotides. Adenine is always paired with thymine, and guanine is always paired with cytosine. These are known as base pairs.
The DNA tells a ribosome how to assemble a protein.