Answer:
the annswer is b
Explanation:
just look at the questin and then see wicth one you can cross off
C. their skin
they have small areas where air can be taken in and released
Answer:
The biological levels of organization of living things arranged from the simplest to most complex are: organelle, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystem, and biosphere.
The ventricles are the pumping chambers. The atria are the receiving chambers.
A GROUP of whatever the class is