It's difficult to pinpoint just two characteristics that make all organisms unique, as there are many aspects that contribute to their individuality. However, two particularly important characteristics are:

1. Genetic Makeup: Each organism has a unique combination of genes inherited from its parents, which influences a vast array of traits, including physical appearance, behavior, and even susceptibility to diseases. This genetic individuality is what makes each organism distinct.

2. Life History: Every organism experiences a unique set of environmental influences and events throughout its lifetime. These experiences shape its development, interactions with other organisms, and overall trajectory, further contributing to its individuality.

While these two characteristics are central to an organism's uniqueness, it's important to remember that other factors like phenotype (observable traits), environment (physical surroundings), and interactions with other organisms also play crucial roles in shaping an individual's life and making it unique.