Answer:
RNA
Explanation:
A ribonucleic acid (RNA) is one of two types of nucleic acid made up of nucleotide subunits. RNA is a single stranded molecule unlike DNA, which is double stranded. The nucleotide unit of nucleic acids is composed of a nitrogenous base (Adenine, Guanine, Cytosine and Thymine/Uracil), a pentose sugar (ribose and deoxyribose) and a phosphate group.
One of the key structural differences between RNA and DNA is that RNA contains URACIL nitrogenous base instead of THYMINE in DNA.
According to this question, a scientist finds that another molecule has contaminated the mixture he is working with in the lab. When he analyzes its chemical structure, he finds that it contains uracil, is single stranded, and contains phosphate. This illustrates that the contaminating molecule is a specific type of nucleic acid called RNA.
