natural selection changes allele frequencies because some survive and reproduce better than others.

Most animal cell membranes have proteins that pump. ions out of the cell and potassium ions into this

The graph shows the amount of global warming happening in different ecosystems. which populations of organisms will likely decline the most as a result of climate change, and why? a.coral reefs because of the loss of the symbiotic algae living within their bodies b.penguin populations because the fish they eat will move into warmer waters c.mountain-dwelling birds because rising sea levels will relocate their food sources d.large cats in the rainforest because of decreased habitat loss for their prey

What materials must dams have to produce electricity, and what must occur?