Risk-taking: Nature or Nurture?

Bob loves excitement. He's a risk-taker. Bob's father was the same, and so was his father's father. What conclusions can we draw from this about why Bob loves excitement and is a risk-taker? Specifically, what can we conclude about what role nature has played in influencing Bob's love for excitement and what role nurture has played in Bob's pattern of behavior? Explain.

Imagine that research has found that children who grow up to be risk-takers more often than not had parents that were risk-takers. What does that indicate about the role nature and/or nurture played in the development of risk-taking behavior? Explain.