How can i tell the difference between a recessive and a dominant

A recessive trait is a trait that needs alleles from BOTH parents in order to show up in the offspring, and is usually portrayed by a lower case letter (a). A dominant trait is a trait that only needs ONE allele from either parent to show up in the offspring, and is usually portrayed by a capital letter (A).

So if the parents had the alleles Aa x aa, then the offspring would be either Aa, Aa, aa, or aa, so they'd have a 50% chance of showing the dominant trait (because there only needs to be ONE capital) and a 50% chance of showing the recessive trait (because there needs to be TWO lower-cases).

A person with a dominant allele for a specific triat always expresses that trait.Even if the other copy of the allele he/she possesses is recessive.If a person possesses two recessive copies of the allele, obtaining one from each parent.For example a person only needs to have one copy of the dimples allele to possess their characteristic, because having dimples is a dominant trait,whereas not having dimples is recessive.