The Tenth Planet of malevolent cyborgs that became a recurring adversary in later "Doctor Who" stories. The "tenth planet" in the title makes reference to a fictional lost planet in Earth's Solar System; at the time of production, the Solar System was generally held to consist of nine planets, prior to the redesignation of Pluto as a minor planet. "The Tenth Planet" is an incomplete "Doctor Who" serial – one of many serials that were affected by the BBC's policy of wiping archived programmes in the 1960s and 70s. Only three of the four episodes are currently held in the BBC archives; the
Sustain Our Planet analysis and a list of recommendations on how a business might reduce its carbon footprint over time. Sustain Our Planet's Green Schools Program is an online teaching resource for children and educators interested in learning and practicing techniques that help protect the planet. This downloadable teaching resource contains green lesson plans, environmentally themed experiments, and green classroom activities on the carbon cycle, saving energy, recycling, and endangered animals. All content compliments the National Standards set by the US Department of Education for Science, English and Art. Sustain Our Planet Sustain Our Planet is a consulting firm that provides carbon calculation