Which statement best explains how organ systems work together to remove wastes?

a. the nervous system controls the movement of food through the
digestive system.

b. the circulatory system carries carbon dioxide away from cells, and
the respiratory system removes it from the body.

c. the respiratory system takes in oxygen, and the circulatory system
delivers it to body cells.

d. the digestive system takes in food and breaks it down into nutrients, and the circulatory system delivers them to body cells.

It is B for A P E X  

Explanation:

B The circulatory system carries carbon dioxide away from cells, and the respiratory system removes it from the body.

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

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