The law of segregation states that allele pairs separate during gamete formation. How then do we have two alleles for a trait? We receive one allele from each parent. ed The alleles join back together before traits are inherited. We receive the two alleles at separate times from one parent.

The law of segregation, proposed by Gregor Mendel, states that during the formation of gametes (sperm and egg cells), the two alleles for a trait separate so that each gamete carries only one allele for each trait. This is a fundamental principle of genetics. To understand how we can have two alleles for a trait despite this separation, let's break down the process: 1. **Alleles**: An allele is a variant form of a gene. For each trait, an individual has two alleles, one inherited from each parent. 2. **Gamete Formation**: During gamete formation (meiosis), the two alleles for a trait segregate from each other. This means that each gamete will receive only one of the two alleles. 3. **Fertilization**: When fertilization occurs, the sperm (which carries one allele) combines with the egg (which also carries one allele). This results in the offspring having two alleles for that trait—one from each parent. So, the correct explanation for how we have two alleles for a trait is that we receive one allele from each parent. The other options provided are incorrect because: - The alleles do not join back together before traits are inherited; they remain separate until fertilization. - We do not receive two alleles at separate times from one parent; each parent contributes one allele. In summary, we have two alleles for a trait because one allele comes from each parent during the process of fertilization after gamete formation.