Skeletal muscle! (or striated muscle).
“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
External skeleton is the correct answer. Hope this helps out !
C. The presence of predators could cause natural selection because it would mean survival of the fittest.
They put a camera up to the microscope! I’ve done that with my phone camera and it’s so cool!
