試題詳解

47. Which of the following is a benefit of blockchain transactions, according to these passages?

(A) immutability.

(B) speed.

(C) transparency.

(D) all of the above.
When life emerged, it did so quickly. Fossils suggest microbes were present 3.7 billion years
ago, just a few hundred million years after the 4.5-billion-year-old planet had cooled enough to
support biochemistry, and many researchers think the hereditary material for these first
organisms was RNA. Although not as complex as DNA, RNA would still be difficult to forge into
the long strands needed to convey genetic information, raising the question of how it could have
spontaneously formed.

Now, researchers may have an answer. In lab experiments, they show how rocks called basaltic
glasses help individual RNA letters, known as nucleoside triphosphates, link into strands up to
200 letters long. The glasses would have been abundant in the fire and brimstone of early
Earth; they are created when lava is quenched in air or water or when the melted rock created
in asteroid strikes cools off rapidly.

The result has divided top origin-of-life researchers. "This seems to be a wonderful story that
finally explains how the nucleoside triphosphates react with each other to give RNA strands,"
says Thomas Carell, a chemist at Ludwig Maximilians University of Munich. But Jack Szostak,
an RNA expert at Harvard University, says he won't believe the result until the research team
better characterizes the RNA strands.