Improvisation of Instructional Materials and Its Effects on Students’ Academic Achievement in Resource-Constrained STEM Classrooms in Owerri Municipal Secondary School, Imo State. JAMS [Internet]. 2026 Sep. 11 [cited 2026 Sep. 21];1(2):Page 1037-1048. Available from: https://jamsjournal.org/JAMS/article/view/improvisation-of-instructional-materials-and-its-effects-on-stud