 Which term best describes Mars' population?
The planet itself was tough enough—barren, desolate, forbidding; enough to stop the most adventurous and dedicated. But they had to run head-on against a mad genius who had a motto: Death to all Terrans! "The surest way to die out here on Mars is to give up." Nothing but what had stopped us could stop a sandcat: sand in the delicate mechanism of the atomic engine. But no; she blamed it all on me somehow: So we were out walking on the spongy sand of the Martian desert. "Maybe there isn't any uranium in this sector at all. Behind us somewhere was the comfort of the Dome, ahead nothing but the mazes and gullies of this dead world. Remember—we're doing this for Earth. Even though the Martian gravity was only a fraction of Earth's, I was starting to tire, and I knew it must have been really rough on Val with her lovely but unrugged legs. She had been just as much inflamed by the idea of coming to Mars to help in the search for uranium as I was. We knew the pay was poor, but we had felt it a sort of obligation, something we could do as individuals to keep the industries of radioactives-starved Earth going. No, we had decided together to come to Mars—the way we decided together on everything. I longed to lie down on the soft, spongy Martian sand and bury myself. I felt almost guilty for having dragged her out to Mars, until I recalled that I hadn't. I stopped, slipped out of the geiger harness, and lowered myself ponderously to the ground. She slid down beside me, curled up, and in a moment she was fast asleep, sprawled out on the sands. Maybe we shouldn't have come to Mars after all. I watched her, sleeping peacefully, a wayward lock of her soft blonde hair trailing down over one eyebrow, and it seemed hard to believe that we'd exchanged Earth and all it held for us for the raw, untamed struggle that was Mars. We just liked our comforts, and wanted to keep them. We had no ties on Earth that couldn't be broken without much difficulty. Heroes. There weren't any Martians, hadn't been for a million years. It had been spun on us only a short time ago, I realized. He wore an outmoded, bulky spacesuit and a fishbowl helmet, all but the face area opaque. I thought I knew everyone on sparsely-settled Mars.
 meager
 congested  meager  sustainable  uninhabited