Answer:
The nucleus.
Explanation:
The nucleus is basically "the boss" of DNA along with housing it. Hope this helps!
If they are both heterozygous black guinea pigs they both carry the allele for white fur. Therefore, the phenotype ratio would be 3:1 (75% offspring will be black furred, and a 25% it will be white furred). You can figure this out by using a punnet square too.