1. **Stating the problem:** A male with blood type AB mates with a female with blood type O. We need to determine the possible blood types of their offspring. 2. **Background:** Blood type is determined by the ABO gene, which has three alleles: A, B, and O. Each person inherits one allele from each parent. 3. **Parental genotypes:** - Male with blood type AB has genotype AB (one A allele and one B allele). - Female with blood type O has genotype OO (two O alleles). 4. **Possible gametes:** - Male can pass on either A or B allele. - Female can only pass on O allele. 5. **Offspring genotypes:** - Combining male and female alleles, offspring genotypes can be AO or BO. 6. **Offspring blood types:** - AO genotype results in blood type A. - BO genotype results in blood type B. 7. **Conclusion:** The offspring can have blood type A or B, but not AB or O. **Final answer:** 1. A or B, but not AB or O.