A botanist decides that he wants to test the effects of ultraviolet light on the growth of plants. Which of the following does NOT need to be kept constant for each of the plants used in this experiment? A. Soil pH B. Air Temperature C. Air Humidity D. Plant growth

When analyzing tree rings, what do scientists assume a thin ring indicates?

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

Scientists discover two populations of mice on either side of a major river. the two populations have almost identical genes but the mice from one side cannot breed with mice from the other. this is most likely because