Photosynthetic cyanobacteria caused an increase in atmospheric levels of a) ozone b) water c) oxygen d) carbon dioxide.

Often, caries will develop in an area of the tooth that's not readily accessible. which cavity preparation form defines this? a. retention b. resistance c. outline d. convenience

Plants consume most of their carbon from a. the soil b. the water c. the roots d. the air

An ecologist studied the same species of deer during the summer and the winter. she noticed that during the summer, when there was plenty of food, the deer were energetic and playful. however, during winter when food was scarce, the deer moved more slowly and did not run unless they needed to escape a predator. which scientific fact is best supported by her observations?