Answer:
The correct option is D
Explanation:
A male sperm needs a x chromosome and y chromosome , whereas a female sperm needs 2 x chromosomes , Thus both genders needing x chromosome
Answer:
The periosteum is one source of precursor cells which develop into chondroblasts and osteoblasts that are essential to the healing of bone. Other sources of precursor cells are the bone marrow (when present), endosteum, small blood vessels, and fibroblasts.
“Genes and environmental effects are often part of the explanation. “
“...disease-causing alleles of one gene may be suppressed by alleles of another gene elsewhere in the genome, or a person's overall health may influence the strength of a disease phenotype.”
https://www.khanacademy.org/science/high-school-biology/hs-classical-genetics/hs-non-mendelian-inheritance/a/polygenic-inheritance-and-environmental-effects