Someseaurchins海胆havevenomous(toxin)spines
When carbon is added to iron in the proper proportions , the result is steel.
Eyespots,themostrudimentaryeyes,arefoundinprotozoan原生动物flagellates鞭毛虫,flatworms扁形虫,andsegmentedworms片段蠕虫.
Communicationisoneofthemostimportantbondsthatholdculturalsystemstogether.
Thefirstpaperwasmadefromthebarkofthemulberrytree.