Why is it advised never to swerve to avoid a deer or other animal?

• Swerving may cause you to strike another vehicle or leave the roadway.
  Explanation:

  "Should a deer or other animal run out in front of your car, slow down as much as possible to minimize crash damage. Never swerve to avoid a deer, as it may cause you to strike another vehicle or leave the roadway, causing more damage or serious injuries."
• Swerving can minimize damage to the vehicle.
• Swerving can scare the animal away.
• None of the above.