Final answer:
In Mendelian genetics, according to the law of segregation, a heterozygous organism has a 50% chance of producing gametes with the recessive allele.
Step-by-step explanation:
The question relates to Mendelian genetics and the inheritance patterns of alleles. According to the law of segregation, a heterozygous organism (one that has two different alleles for a trait) has a chance of producing gametes with the recessive allele. During gamete formation, alleles for a trait segregate so that each gamete carries only one allele for each gene. This results in a 50% chance of transmitting either allele to the offspring. If an organism is heterozygous for a given trait (Aa), then it has two different alleles: one dominant (A) and one recessive (a). Thus, there is a 50% chance that a gamete produced by a heterozygous organism will contain the recessive allele (a).
Therefore, the correct answers to fill in the blanks would be:
Segregation
50%