Please what's an ecosystem​

All annelids and arthropods have a blank body plan . unlike annelids, arthropods also have blank . the circulatory system of annelids is blank , while circulatory system of arthropods is blank .

Acid rain throughout the northeast united states has lowered the ph of many ponds and lakes. the lowered ph will eventually result in the death of many aquatic animals. compare the map of the u.s. with the ph tolerance range for the organisms listed. based on the tolerances seen here, which aquatic organisms are least likely to survive in the northeastern states?

Which of the following factors would not contribute to allopatric speciation? a) the isolated population is exposed to different selection pressures than the ancestral population.b) a population becomes geographically isolated from the parent population. c) gene flow between the two populations is extensive.d) the separated population is small, and genetic drift occurs. e) different mutations begin to distinguish the gene pools of the separated populations.