Answer: B) Dr. James Lovelock
Dr. Lovelock first came up with the Gaia hypothesis, which "proposes that living and nonliving parts of the earth are a complex interacting system that can be thought of as a single organism," after studying life on Mars for NASA in the 1960s. In 1979 he published a book-- Gaia: A new look at life on Earth--in which he popularized the concept. While the hypothesis has entered the popular lexicon and has become especially popular among environmentalists, it is controversial in the scientific community. Regardless of its scientific merit, the Gaia hypothesis is extremely useful for thinking about the world, and our impact on it, in holistic terms.