This research aims to analyze the understanding of students’ concepts in 9th grade junior high school on genetic material. Mastery is one important process learning biology. In this research, it used case study method with design pretest only group design. The number samples 50 students consisting 35 female and 15 male students. average sample 14--15 years old. instruments consist multiple choi...

Controversial studies on the jet collimation profile of BL Lacertae (BL Lac), eponymous blazar Lac objects class, complicate scenario in this already puzzling class objects. Understanding geometry, connection with kinematics and physical conditions surrounding medium, is fundamental to better constrain formation, acceleration mechanisms extragalactic jets. With aim investigating geometry innerm...