Answer:
circulatory and respiratory
Explanation:
The body system of Birds possesses a higher arrangement of organs to perform a particular function. The organs form a system which includes the organs and associated structures.
When the biologist observed the shortage of the dissolved oxygen and increase in the level of dissolved carbon dioxide, this could be the result of the failure of the circulatory system which supplies these gases on the body and the associated respiratory system which helps in the exchange of these gases with the atmosphere.
Thus, circulatory and respiratory is the correct answer.
Hydrogen isn’t one of the primary macronutrients
