Context: Trying to snap a two-game losing streak and avenge their Week 5 collapse, the Texans flew to Lucas Oil Stadium for a Week 11 AFC South rematch with the Indianapolis Colts.  In the first quarter, Houston struck first as kicker Kris Brown got a 28-yard field goal.  The Colts responded with kicker Adam Vinatieri getting a 40-yard field goal.  The Texans would answer with Brown making a 34-yard field goal.  In the second quarter, Indianapolis tied the game with Vinatieri getting a 39-yard field goal.  Houston replied with RB Ahman Green getting a 1-yard TD run.  The Colts closed out the half with Vinatieri making a 32-yard field goal. In the third quarter, Indianapolis got the lead as QB Peyton Manning completed a 23-yard TD pass to RB Joseph Addai.  The Texans regained the lead as rookie RB Steve Slaton getting a 71-yard TD run.  The Colts would answer with Addai getting a 7-yard TD run.  In the fourth quarter, Indianapolis increased their lead as Manning completed a 10-yard TD pass to WR Marvin Harrison.  Houston tried to come back as Green got a 2-yard TD run, but the Colts pulled away as Vinatieri nailed a 31-yard field goal.

Question: Who scored the first touchdown?

Answer:
Ahman Green