Answer:
proto-oncogenes are normal genes while onco genes are cancerous genes.
Explanation:
Proto-oncogenes are genes which responsible to make protein and helps in controlled cell growth and proliferation but some time these proto-oncogenes can turned into onco genes because of some abnormal mutation and results in uncontrolled proliferation and cell growth which cause cancer.
Compare: They both are products of DNA. They both are equally important to a living organism. Contrast: Genotype is the genetic makeup, while Phenotype is the physical appearance. Genotype can't be seen but phenotype can.