Scientists theorize that it took a billion years or more for oxygen in the atmosphere to reach the levels of today. Based on this idea, the first cells that appeared on Earth could be classified as which of the following?

Which process can increase the rate of greenhouse gas emissions into the atmosphere in response to a decrease in albedo

According to the cladogram, which organisms have roundworms as a common ancestor?

Drag each tile to the correct box. the body monitors the levels of oxygen in the blood to regulate breathing. isabel is running in a marathon and is near the finish line. she feels out of breath. how will her nervous system work to generate a reaction? arrange the tiles in chronological order. isabel's breathing rate increases. sensory receptors in the arteries detect low oxygen levels. the brain sends signals through motor neurons. sensory neurons generate an impulse. the central nervous system relays an impulse to certain brain regions.