What term is used for the study of nonliving parts of earth? ecology biology geology (pretty sure it's ecology)

When does the circulatory system work with the respiratory system? a. during blood cell formation b. during cellular respiration c. during intestinal digestion d. during a viral infection

Which anatomical plane is the only one that could not show both the sternal region and vertebral region

The diagram shows a chicken embryo and a human embryo