However, since "GDZ" refers to specific educational answer keys used in Russian curricula, the best sites to find this particular manual are usually: : One of the largest databases; very mobile-friendly. Reshak.ru : Great for step-by-step explanations.

It sounds like you're looking for an easy way to access the for the Biology textbook by Sumatohin and Kuchmenko online without having to download any files.

Try to solve the problem yourself first. Use the GDZ as a "hint" or a way to verify your logic, rather than just copying. This helps the information actually stick for your next test.