Final answer:
Based on the fact that black is dominant over white in poodles and a litter resulted entirely in black puppies from a cross of black and white poodles, the best conclusion is that some of the puppies will be black in future litters, as this accounts for the unknown genotype of the black poodle. The correct answer is option 2.
Step-by-step explanation:
In poodles, black fur is dominant over white fur. When a black poodle is crossed with a white poodle, and all the offspring in a litter are black, this suggests that the black poodle was likely homozygous dominant (BB) for the trait.
If the black poodle had been heterozygous (Bb), we would expect approximately half of the puppies to be white, assuming the white poodle was homozygous recessive (bb). Since all the puppies in the given litter are black, we could tentatively conclude this, but more litters would be needed to confirm the black poodle's genotype.
For future litters, it would be incorrect to assert that all puppies will necessarily be black as different genetic combinations can occur. However, since we only have information on one litter, the best conclusion we can draw is that some of the puppies will be black in future litters, which accounts for the possibility of the black poodle being heterozygous. Therefore, the correct option for this question is 2) Some of the puppies will be black in future litters.