This study aims to design and produce Student Worksheets (LKPD) based on the Student Teams Achievement Division (STAD) on class XI human respiratory system material. This type of research is Research and Development (Reasearch & Development) with the ADDIE model (Analysis, Design, Development, Implementation and Evaluation). The subjects of this study were 2 material expert validator lecturers and 2 learning expert validator lecturers, the assessment of 1 biology teacher, and the responses of class XI MIPA-3 students of SMAN 1 Labuhan Deli T.A. 2022/2023. Data analysis used quantitative and qualitative descriptive analysis. The results showed that the development of STAD-based LKPD obtained validation results by material experts of 96.88% in the "very feasible" category, validation by learning experts of 90.13% in the "very feasible" category, assessment by biology teachers of 93.42 % in the "very feasible" category, the student response was 94.96% in the "very feasible" category, and the results of the effectiveness test obtained an N-gain score of 0.72 which was included in the "high" category and was considered effective in being used in the learning process biology in the material of the human respiratory system.

Indonesia adheres to a democratic government system that relies on the principle of checks and balances. This principle is inherent in the legislative institution, namely the DPR, which has the right to carry out its duties, one of which is the right to inquiry. In the election context, the right to inquiry can be used to investigate fraud or violations that occur in the election administration process. However, the use of the right to inquiry currently still raises pros and cons among the public. In response to this, this research aims to understand the juridical considerations regarding the right to inquiry in holding elections and analyze the influence of the right to inquiry on elections. The method used in this research is descriptive normative law by studying or reviewing primary and secondary legal materials. This research shows that the DPR’s right to inquiry cannot influence or cancel the election results. However, the DPR’s right to inquiry can be used to request information from the government regarding the implementation of elections.

Education plays an important role in shaping students' character and competence. One of the challenges faced by the world of education is how to build students' understanding of subject matter that is relevant to the context of their daily lives. In this case, ethnomathematics is a very potential approach to be applied in mathematics learning. The purpose of this study is to examine the effectiveness of ethnomatics-based mathematics learning to strengthen cultural values. This study uses a Qualitative research method with a case study approach. This approach allows researchers to explore the experiences, perceptions, and impacts of ethnomathematics learning on students and teachers. The research subjects consisted of: students, teachers and parents. The results of this study indicate that ethnomathematics can improve students' mathematics learning achievement, especially in terms of identifying, translating, understanding the meaning of symbols, understanding and applying mathematical ideas, and making an exploration (estimate) related to mathematical concepts that is better than conventional learning.

The aim of this research is to find out the process carried out by CSR PT. KAI (Persero) in carrying out programs organized through disabled friends starting from fact finding, planning and programming, taking action and communications, evaluating. Research from this theoretical basis refers to the Four Steps of Public. Relations discovered by Cutlip, Center, and Broom. Referring to the chosen theory, it is able to construct the overall process both in formulating indicators and collecting data regarding the CSR program for friends with disabilities. The results of this research show that PT Kereta Api (Persero)'s Corporate Social Responsibility in Strengthening the Friends of Disabled Program is considered effective. Carrying out a program for the welfare of people with disabilities is an effort to build the company's image in the eyes of the community by providing services both morally and materially. Thus, through the disabled friends program, the public's perception of PT. KAI (Persero) is a company that supports and is friendly to people with disabilities.

Islamic religious education is education that teaches the values of goodness which then its implementation is applied in life. Islamic education itself has an important role in the history of the development of the Indonesian nation, especially in terms of the historical dimension where Islamic education has been a formal education for centuries known as pesantren. The purpose of this study is to determine the relationship, the role of Islamic education in the national education system because to make a person who is balanced from an intellectual perspective, religious education is needed, namely Islamic education in order to achieve the goals of national education. The method used in this research uses qualitative research methods with the type of library research. Based on the research results, it can be concluded that Islamic education in the national education system is Islamic education occupying a position as a formal, non-formal, informal, and religious institution.