D) a change in protein synthesis
The Integumentary System.
Answer:
Explanation:
The cells in our bodies need oxygen to stay alive. Carbon dioxide is made in our bodies as cells do their jobs. The lungs and respiratory system allow oxygen in the air to be taken into the body, while also letting the body get rid of carbon dioxide in the air breathed out.
The last one...the species is unable to reproduce in any habitat beyond a population of 300 individuals
