Which of the following is NOT considered an example of adaptation?

The red color of mammalian blood is not considered an example of adaptation in the same context as the other options. Adaptations are traits that have evolved over time in response to environmental pressures, enhancing an organism's chances of survival and reproduction.

Bird feathers serve important functions such as insulation, protection, and aiding in flight, making them adaptations to various ecological niches. Likewise, the longer necks of giraffes are thought to be adaptations that facilitate feeding from tall trees and possibly engaging in necking behavior during mating contests, thereby improving their chances of survival and reproductive success.

Africanized honey bees displaying aggressive behavior is also an adaptation; their heightened defensiveness is a trait that has evolved to protect their hives from predators, thus increasing survival rates for the colony.

In contrast, the red color of mammalian blood primarily arises from the presence of hemoglobin, which is essential for transporting oxygen. This characteristic is a biochemical necessity rather than a trait that evolved specifically due to environmental pressures to improve fitness. The red color itself does not enhance survival or reproductive success in a direct adaptive sense.