“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
Answer: Loss of biodiversity appears to affect ecosystems as much as climate change, pollution and other major forms of environmental stress, according to results of a new study by an international research team. ... Studies over the last two decades demonstrated that more biologically diverse ecosystems are more productive.hope this helps:)!
