The different in sequence in a gene could result in one boy being albino and the other boy having normal skin color

Albinism is a recessive characteristic of the absence of skin and hair color pigment melanin. Albinism is actually caused by an enzyme gene defect that synthesizes melanin. The central molecular biology dogma explains that the DNA sequence specifies the mRNA sequence that also specifies protein sequence codes. Because a gene is a segment of DNA, the altered gene causes altered mRNA that causes altered protein. Therefore, an enzyme defect synthesizing melanin in the gene will cause the absence of melanin.

b. the carbon cycle ensures living things have a source of hydrogen