What is formed by groups of cells which work together as organs in organ systems?

What are two reasons for why a species might disappear from the fossil record?

An example of internal feedback working to maintain homeostasis is your a. decreased respiration rate when you are studying b. decreased heart rate when you are sad c. increased respiration rate when your muscles need more oxygen d. increased heart rate when your lungs need more oxygen

Whats one way that rocks do not follow the typical rock cycle pathway?