Question

read the passage. keeping preemies warm premature babies—born three or more weeks short of a full - term pregnancy—often lack vital body fat, putting them at risk of dangerously low body temperatures. such \preemies\ can be warmed in hospital incubators. however, incubators are not always a viable solution in lower - income countries. hospitals in poor countries often cannot afford the equipment, and the hospitals that do have incubators are typically located only in urban areas. many rural families are unable to transport their preemies such long distances, and those who make the trip can generally remain at the hospital for only a few days. a group of students at stanford university developed a solution: an inexpensive, portable baby warmer for home - based use. similar to a small sleeping bag, the warmer contains a heating pouch which, once warmed, maintains a temperature of 98.6°f for four hours. thanks to this innovation, thousands of preemies have been saved. what is the main, or central, idea of the passage? premature babies, at risk of life - threatening low body temperatures, must be kept in a warm environment. stanford students developed a baby warmer for use in the home, saving the lives of premature babies whose families lack access to incubators. students at stanford university designed a sleeping - bag - like baby warmer that can remain at 98.6°f for four hours after being warmed.

Explanation:

The passage first describes the problem of preemies being at risk due to low - body temperatures and the limitations of hospital incubators in lower - income countries. Then it focuses on the solution developed by Stanford students: a home - based baby warmer that has saved many preemies. The main idea should encompass the problem and the solution. The first option only mentions the problem, the third option only details the product. The second option includes both the problem (families lack access to incubators) and the solution (Stanford students developed a home - based baby warmer to save preemies).

Answer:

Stanford students developed a baby warmer for use in the home, saving the lives of premature babies whose families lack access to incubators.