Start with B, add a word to get answer.
-1.B + most elderly = bravest. 7 letters
-2.B + protective device = prevent. 5 b---k
-3.B + distribute = vote. 6
-4.B + sheep = cow. 6 b----e
-5.B + home area = besom. 5
-6.B + expose to loss = invigorating. 5
-7.B + precipitation = thought organ. 5
8.B + sot = redden. 5 b---h
-9.B + correct = intelligent. 6
-10.B + hurry = artist tool. 5