Which came first, the chicken or the egg? This is one of life’s __1__ questions and people have been debating about it for thousands of years. Now scientists believe they have solved this _2__. Researchers from Sheffield and Warwick Universities in England discovered the answer __3__. They used a super computer to observe the shell-making process while a new shell was __4__. Then they found one protein called OC17 that is __5__ for forming eggshell. This is only found inside a chicken’s body, which is proof that the _6__ came first. The team was __7__ looking at how animals and birds make eggshells but suddenly made their surprising __8__. The big question now is where chickens came from. The _9__ is from dinosaurs.
The research team said eggshells are one of nature’s most __10__ creations. Professor John Harding from the team told reporters: “Understanding how chickens make eggshells is fascinating in itself, but it can also be __11__ in designing new materials.” Eggshells are very lightweight but incredibly strong. Even the most up-to-date materials __12__ by the world’s top engineers can not produce anything as __13__ as an eggshell. Professor Harding added that __14__ eggshells could help to cure bone diseases and design materials for the construction industry.“Nature has found wonderful ways that __15__ for all kinds of problems in materials science and technology — we can learn a lot from them.” he said.

A．strangest B．best C．oldest D．longest

A．puzzle B．story C．history D．idea

A．on purpose B．by chance C．without hesitation D．at work

A．breaking B．changing C．disappearing D．forming

A．necessary B．easy C．kind D．impossible

A．egg B．eggshell C．chicken D．dinosaur

A．obviously B．originally C．thoughtfully D．surprisingly

A．invention B．mistake C．statement D．discovery

A．answer B．research C．key D．egg

A．strange B．ridiculous C．funny D．amazing

A．hopeful B．helpful C．respectful D．colorful

A．bought B．cut C．designed D．carried

A．brilliant B．ordinary C．1ight D．strong

A．finding B．watching C．studying D．making

A．happen B．work C．wait D．look