1.
a) strengthen
b) strengths
2.
a) lengthen
b) length
3.
a) deafening
b) Deafness
4.
a) depth
b) deepened
5.
a) widened
b) width
6.
a) weakened
b) weakness
7.
a) shortened
b) shortness
8.
a) height
b) height