SAN FRANCISCO -- A review of four hot issues from the San Francisco 49ers' 10-9 loss to the Carolina Panthers:Offense sputters: The 49ers lost this game on offense. The defense was terrific, but the offensive was lackluster, especially in the second half. All the 49ers had to show for the game was three first-half field goals. The 49ers had just 45 total yards in the second half, and quarterback Colin Kaepernick threw for 91 yards and was sacked six times, a season high.