{Reference Type}: Journal Article {Title}: A nonautonomous model for the interaction between a size-structured consumer and an unstructured resource. {Author}: Ni Z;Huang Q; {Journal}: J Math Biol {Volume}: 88 {Issue}: 5 {Year}: 2024 Mar 28 {Factor}: 2.164 {DOI}: 10.1007/s00285-024-02071-2 {Abstract}: In this paper, we propose and analyze a nonautonomous model that describes the dynamics of a size-structured consumer interacting with an unstructured resource. We prove the existence and uniqueness of the solution of the model using the monotone method based on a comparison principle. We derive conditions on the model parameters that result in persistence and extinction of the population via the upper-lower solution technique. We verify and complement the theoretical results through numerical simulations.