Final answer:
Complex genetic interactions (option c) are NOT an advantage of using Arabidopsis thaliana as a model organism because they can complicate experiments and the interpretation of gene functions.
Step-by-step explanation:
The question is asking to identify which point listed is not an advantage of using Arabidopsis thaliana as a model organism. Among the options provided: a) Short life cycle, b) Small genome size, c) Complex genetic interactions, and d) Ease of genetic manipulation, the one that is not an advantage is c) Complex genetic interactions.
This is because complex genetic interactions can make it more difficult to deduce gene functions and may complicate experimental results. In contrast, a short life cycle, small genome size, and ease of genetic manipulation are all advantages that make Arabidopsis thaliana a favourable model organism for genetic studies.