As the offspring inherits one allele from each parent, it will obtain only the B allele from the female mouse and either the B or b allele from the male mouse. Hence possible offspring genotypes are BB or Bb with 0.50 probability each (each probability of either genotypes being present in the offspring).
Hmm due to some thinking and having some knowledge of the body. I believe the crani refers to the skull. Crani could be considered short for cranium which refers to the skull. I hope that this helps!
