Unliketraditionalgyms,app-backedgymsofferpeople___________optionstoexercise.
Someseaurchins海膽havevenomous(toxin)spines
Eyespots,themostrudimentaryeyes,arefoundinprotozoan原生動物flagellates鞭毛蟲,flatworms扁形蟲,andsegmentedworms片段蠕蟲.
Someanimalspantandsweattospeedevaporationofbodymoistureandthuscoolthemselves.
習慣是指什么？
