To determine which Punnett square shows a 100% probability that cattle offspring will be homozygous dominant for red hair, you need to identify a square where both parental genotypes contribute only the dominant allele for red hair.
Assuming that 'R' represents the dominant allele for red hair and 'r' represents the recessive allele, the following combinations would lead to 100% homozygous dominant offspring:
- RR x RR: All offspring will be RR (homozygous dominant).
- RR x Rr: All offspring will be either RR or Rr, but there will be no rr (homozygous recessive).
- Any combinations involving at least one 'rr' (like Rr x rr) are not suitable as they will produce a mix of genotypes.
Please review the Punnett squares you have and look for one where both parents contribute 'R' alleles only (like RR x RR). If you can provide the specific options, I can help you determine which one meets the criteria.