Answer:
1/2 or 50%
Step-by-step explanation:
B is dominant over b and T is dominant over t.
BbTt is crossed with BBtt
BbTt x BBtt = 4 BBTt, 4 BBtt, 4 BbTt and 4 Bbtt
4 BBTt = black fur with short tail
4 BBtt = Black fur with long tail
4 BbTt = Black fur with short tail
4 Bbtt = Black fur with long tail.
8 of the offpring have black fur with long tail while 8 also have black fur with short tail.
The proportion of offspring having black fur with long tail is 1/2 or 50%.