Although the Carbon 14 method of dating old objects is not foolproof , it is the best method available at present
A、whollyoperationalC
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Thefirstpaperwasmadefromthebarkofthemulberrytree.
With lasers scientists can probe many physical processes, such as combustion, once beyond our ken.视野
Someseaurchins海胆havevenomous(toxin)spines
Alllivingorganisms,regardlessoftheiruniqueidentity,havecertainbiological,chemical,andphysicalcharacteristicsincommon.
Eyespots,themostrudimentaryeyes,arefoundinprotozoan原生动物flagellates鞭毛虫,flatworms扁形虫,andsegmentedworms片段蠕虫.
