The document introduces two 12-year-old girls, Judith and Marta, who both recycle plastic, paper, and glass at home. Judith recycles additional materials like aluminum and comes to school by car in the mornings and walks the rest of the day, while Marta comes and returns from school by car. It defines recycling as reusing materials to create new materials and explains that recycling helps save the planet. The girls' green motto is to save energy.