Which of the following is a primary abiotic factor affecting organisms?

Temperature is indeed a primary abiotic factor affecting organisms because it is a fundamental element of the environment that influences many biological processes. Abiotic factors are non-living chemical and physical components of the environment, and temperature significantly impacts metabolic rates, enzyme activity, and overall physiological functions in living organisms. For instance, temperature variations can dictate the types of species that can thrive in a particular habitat, influencing their distribution and behavior.

In contrast, the other choices represent biotic factors or elements influenced by living organisms. Predators and competition relate to interactions between organisms, which are not classified as abiotic. Plant life, while an essential component of many ecosystems, is also biotic since it involves living organisms. The fundamental nature of temperature as a non-living environmental factor places it distinctly as an abiotic influence on ecosystems and organisms.