Answer:
what do you need help with?
Explanation:
The scientific theory of evolution states that populations change over time in response to changes in the enviroment
Respiratory system= breathing system
To keep our Respiratory system healthy we should:
1- never breathe in front of polluted areas
2- never pollute our areas
3- try to make our environment normal
Answer
A thick grouping of nerves that run down the back of the embryo
Explanation
The dorsal nerve cord is special embryonic characteristic of the ganglia. It is a hollow dorsal cord that is composed of a section of the exfoliated coagulant that forms a hollow tube unlike solid abdominal tubes in other animal species. It is located in the vertebrae of vertebrates.
