Pls help! on gregor mendel

P, F₁, and F₂

Explanation:

The parental generation is also known as P.  F₁ is the first generation and F₂ is the second generation.  

answer; a male inherits only one allele of the x-linked gene controlling hair color;

the sugar-phosphate backbone forms the structural framework of nucleic acids, including dna and rna. this backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.