Answer:
Step-by-step explanation:
In this quote from "The Martian" by Andy Weir, the speaker is explaining how the water reclaimer in the Hab (the habitat where they live) on Mars works and how it relates to their water supply. The Hab has an efficient water reclaimer, the best technology available on Earth, which can recycle and purify water. This advanced technology led NASA to decide not to send a large amount of water from Earth to Mars, but only enough for emergencies.
The speaker mentions that humans need three liters of water per day to be comfortable, and they were given 50 liters of water each, totaling 300 liters in the Hab. The speaker is willing to dedicate all but an emergency 50 liters for a specific cause.
The speaker then uses the amount of water available to calculate their ability to grow plants (feed) in the Hab. They mention that with the water available, they can support the growth of plants in an area of 62.5 square meters at a depth of 10 centimeters, which is about two-thirds of the Hab's floor. This is their long-term plan for sustaining themselves on Mars.
However, the immediate goal for the day was to cultivate plants in a smaller area of five square meters. The quote showcases the speaker's resourcefulness and practical approach to solving problems while surviving on Mars.