The Salk vaccine is a major factor in the fight to eradicate polio.
A、completelydestroyA
暂无解析
Eyespots, the most rudimentary eyes, are found in protozoan原生动物 flagellates 鞭毛虫 , flatworms 扁形虫 , and segmented worms片段 蠕虫 .
All living organisms, regardless of their unique identity, have certain biological, chemical, and physical characteristics in common.
ThefuturesurvivalofthebaldeagleisstillanimportantAmericanecologicalconcern.
The controls of most modern airplanes can be operated either manually or automatically.
Alllivingorganisms,regardlessoftheiruniqueidentity,havecertainbiological,chemical,andphysicalcharacteristicsincommon.
