Which statement explains one way that lakes form? O Lava flows block a river.
Streams flow into shallow areas.
O Groundwater feeds into low-lying areas.
O Grassy wetlands get covered by a stream.

After fertilization, which type of cellular division is responsible for the growth and development of a complex, multicellular organism?

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.

List five ways we are indebted to phytoplankton