Complex sentence: Ms. Martha Karua was a key member of the opposition politicians who struggled for the reintroduction of multi-partyism in the 1990s, and later formed a coalition movement that won power in 2003.
Split into simpler sentences: Ms. Martha Karua was a member of the opposition politicians who struggled for the reintroduction of multi-partyism in the 1990s. Later she was among those forming a coalition movement that won power in 2003.