Final answer:
The probability of offspring having long or short ears in horses depends on the parents' genotypes. Without information on the parent horses' genetic makeup, a specific probability cannot be determined. Typically, Mendelian genetics would be used to calculate these probabilities if the trait follows a simple dominant-recessive pattern.
Step-by-step explanation:
The probability of horses having long ears or short ears is not provided in any of the excerpts, but it is likely tied to the genetic makeup of the specific horses. If we assume that ear length in horses follows a simple Mendelian trait, and one allele for ear length is dominant over the other, we would need to know the particular genotypes of the parent horses to predict the probability of their offspring having long or short ears.
For a more general example based on Mendelian genetics, if long ears were dominant (L) and short ears recessive (l), and both parents were heterozygous (Ll), using a Punnett square we could predict that the genetic combinations would be 25% LL (long ears), 50% Ll (long ears), and 25% ll (short ears). So in this case, the probability for the offspring having short ears would be 25%, not the options provided. Answer D) It depends on the specific genetic makeup of the parent horses reflects this variability.