Question

aerogels are highly porous foams consisting mainly of tiny air pockets within a solidified gel. these lightweight materials are often applied to spacecraft and other equipment required to withstand extreme conditions, as they provide excellent insulation despite typically being brittle and eventually fracturing due to degradation from repeated exposure to high heat. now, xiangfeng duan of the university of california, los angeles, and colleagues have developed an aerogel with uniquely flexible properties. unlike earlier aerogels, duan’s team’s material contracts rather than expands when heated and fully recovers after compressing to just 5% of its original volume, suggesting that ________ which choice most logically completes the text? a) the aerogel’s remarkable flexibility results from its higher proportion of air pockets to solidified gel as compared to other aerogels. b) the aerogel’s overall strength is greater than that of other insulators but its ability to withstand exposure to intense heat is lower. c) the aerogel will be more effective as an insulator for uses that involve gradual temperature shifts than for those that involve rapid heat increases. d) the aerogel will be less prone to the structural weakness that ultimately causes most other aerogels to break down with use.

Explanation:

The text emphasizes the new aerogel's unique properties like contracting when heated and fully recovering after high - compression. These properties suggest it is less likely to suffer from the structural weaknesses that cause other aerogels to break down. Option A has no basis in the text about air - pocket proportion. Option B has no comparison of strength and heat - withstand ability in the text. Option C has no information about different types of heat increases in the text.

Answer:

D. the aerogel will be less prone to the structural weakness that ultimately causes most other aerogels to break down with use.