What is the relationship between mixing and melting, is it physical change or physical property, or anything else?

In the family tree below, people with the recessive trait of attached earlobes are shaded gray.

What is a cordon and where is it found

The structure of a dna molecule is best described as a. one long strand of nucleic acids b. two strands of dna nucleotides joined by hydrogen bonds c. two strands of amino acids joined by hydrogen bonds d. one long strand of amino acids