Working from deep geologic strata toward shallow geologic strata, what is the sequence in which fossils of these groups should make their first appearance?
1. charophytes
2. single-celled green algae
3. hornworts
4. plants with a dominant sporophyte

Internal feedback works to maintain homeostasis when your a. heart rate decreases as your white blood cells increase b. breathing rate decreases as your red blood cells decrease c. heart rate increases as your liver is cleaning blood d. breathing rate increases as your heart rate increases