They both are types or categories of nitrogen containing bases present in nuclei acids of DNA and RNA.
Purines are 2 Ring or Carbon Ring, Nitrogen containing bases. That consist of these 2 rings next placed next to each other. These examples include - Adenine and Guanine.
Pyrimidines are 1 or single Ring Nitrogen containing structures. There are 3 nitrogenous bases that are categorized as pyrimidines. Cytosine, Thymine, and Uracil.
The statement that best describes an external circuit is "<span>D. The flow of an alternating current switches direction when a generator's terminals change its charge." The main difference between direct and alternating current is the direction of flow. Direct current follows only one direction from negatve to positive, while alternating current changes direction periodically.</span>
The Answer is= 7.8 x 10^4
Answer:a number without a decimal are generally not significant. Isotopes are atoms of same element which have the same atomic number but different number of neutrons. Isotopes of elements are represented in the following way: In an atom, the number of protons is equal to its atomic number.. An atom of an element is neutral in nature so atom contains the same number of protons and electrons.
Explanation: