Part A In "Earthships," what can be inferred about why people would use passive solar? It aids in the collection of "gray" water. It is a superior source of natural gas. It is the only viable source of heat on an Earthship. It is an economically practical alternative to electricity. Question 2 Part B Which evidence from the passage best supports the answer to Part A? "Now, long-term studies have revealed some problems. For one, without sufficient sunlight during the winter, large amounts of natural gas known as propane and/or wood are used to heat the home. " "During the summer, the combination of the cool temperature of the earth beneath the floor plus the thick walls can keep the house comfortable without the use of air-conditioning." "Building an Earthship may be an attractive choice for those who want to use fewer of our planet’s non-renewable resources." "Floor-to-ceiling windows on an Earthship's south wall also allow plenty of sunlight."