Acid rain is caused by which of the following?
nitrogen compounds in plants
nitrogen compounds in the air
nitrogen compounds in the soil
nitrogen compounds in lakes and rivers

Examine the two squirrel populations in the accompanying figure. the populations are separated by a geographic barrier. if after a long period of time the two species are no longer separated, what evidence is needed to determine if speciation has occurred? the figure shows two populations of squirrels separated by a geographic barrier. examine the two squirrel populations in the accompanying figure. the populations are separated by a geographic barrier. if after a long period of time the two species are no longer separated, what evidence is needed to determine if speciation has occurred? the figure shows two populations of squirrels separated by a geographic barrier. polyploidy is creating new species. the two populations are not interbreeding freely. hybrid offspring of the two populations begin to appear. one species will increase into a population size twice as large as the other species.

What are the characteristics of subsystem

Match the order of the levels of organization in nature with the correct description. example: atoms are fundamental units of matter= level 1levels- 2,3,4,5,6,7,8.now what levels are these? population consists of organismscells consist of moleculesecosystems consist of communities interacting with there environmentmolecules consist of atomsthe biosphere consist of all ecosystems on earthcommunities consists of populationorganisms consist of cells