1) Traits controlled by dominant alleles will always be expressed when the allele is present, while recessive traits only appear if no dominant alleles are present. Co-dominant alleles are neither dominant nor recessive and both alleles are expressed in offspring. 2) Geneticists use Punnett squares to determine all possible outcomes from genetic crosses and the probability of particular traits being expressed in offspring. The squares show how parental alleles combine. 3) The Human Genome Project aimed to sequence all human genes to better understand disease inheritance and find cures, but raised ethical debates around possibilities like designer babies.