Fibrinogen plays an important role in blood clotting.

He worked hard to accomplish his goals.

He said that his blood type is A.

His role is the team leader.

Health is very important.

His opinion is very important.

He received the letter challenging him to a duel and began preparing for the duel.

My blood type is A.

Gender roles are an important element in defining individual behavior in society.

His role is to fulfill his responsibilities as a leader.