This is a cell, which is the basic unit of all life. All organs in human bodies are made of cells and require oxygen to survive. Which two systems work together to deliver oxygen to cells throughout the body?

A) skeletal and endocrine

B) digestive and endocrine

C) skeletal and respiratory

D) respiratory and cardiovascular

The blood circulatory system (cardiovascular system) delivers nutrients and oxygen to all cells in the body. It consists of the heart and the blood vessels running through the entire body.

So the answer is D) respiratory and cardiovascular

Explanation:

For example, the respiratory system and the circulatory system work closely together to deliver oxygen to cells and to get rid of the carbon dioxide the cells produce.

The two systems that work together to deliver oxygen are D, respiratory and cardiovascular