No caffein,there is a factor that must not be changed when conducting an experiment,known as controlled variable
According to this principal, if a recessive gene for tallness is paired with another recessive gene for tallness, the organism is categorized as a homozygous recessive in terms of its genotype.
For humans, we have 19,000 protein-coding genomes. For every gene, there are 2 alleles. This means that humans have 38,000 alleles (19,000×2=38,000).
