The provided question is incomplete as it lacks the combinations of parent as metion in the question, however the complete question is attached as the image.
Answer:
There are two parent combinations that are :
1. heterozygous black Ff cross with heterozygous black Ff
2. heterozygous black Ff cross with white ff
Explanation:
1. in first combination the each parent will produce F and f gametes, as it is shown as Capital F so it will be dominant over f as per the rule. so the cross can be shown as :
F f
F FF Ff
f Ff ff
where, FF are black Ff black and ff white offspring. As there is clearly 3 black offspring over one white spring so the ratio is 3:1 or 75% chances of black and 25% chances of white offspring (phenotype).
2. in second combination there would be F and f gametes for black parent and f and f for white parent, thus the offsprig would be :
F f
f Ff ff
f Ff ff
As, there is two black and two white springs are produced than the ratio would be 2:2 or 50% chances of each white offspring and black offspring (phenotype)
