What element has 2 energy levels and 1 valance electrons

In dna, only the_ varies from one nucleotide to another. base phosphate sugar amino acid

Which is a genetic engineering advancement directly related to a career in biotechnology? 1) improving solar energy collection 2) transporting textiles at higher rates 3)creating crop foods that resist insect pests 4)repairing historical sites with quality materials

In each transformation of energy , some energy what?