1. the breeding of two organisms that differ in a single trait monohybrid cross 2. the expression of a genetic trait; what the trait looks like phenotype 3. a phenotype (trait) resulting from homozygous genes from the offspring of true breeding purebred 4. a gene or trait that is masked when a dominant allele is present self-fertilization 5. when an organism that possesses both male and female gametes brings the two genetically identical gametes together to produce offspring recessive

The correct matching is as follows:  

1. Monohybrid cross refers to the breeding of two organisms, which vary in just a single trait.  

2. Phenotype refers to the expression of a genetic trait, that is, what the trait looks like.  

3. Purebred refers to the trait originating from homozygous genes from the offspring of true breeding.  

4. A recessive gene refers to a gene or trait, which is masked when a dominant allele is present.  

5. Self-fertilization refers to the procedure when a species that exhibits both male and female gametes makes the fusion of both the identical gametes to produce offspring.