The system includes the lungs. a. endocrine b. immune c. respiratory d. circulatory

C. respiratory

Explanation:

The lungs are the vital organs which are the part of the respiratory system. A respiratory system consists of specialized organs both in plants as well as in animals which helps in the process of exchange of gases. The two lungs consists of network of blood vessels and tubes where gaseous (carbon dioxide and oxygen) exchange takes place. The tubes and blood vessels includes the brochioles, the alveoli and the capillaries. The oxygenated blood from the lungs is transported to heart for circulating it to all the parts of the body.  

a chair, a bed, and a toothbrush

explanation:

igneous rocks which formed by the crystallization of magma at the surface of the earth called extrusive rocks. they are characterized by fine-grained textures because the rapid cooling at or near the surface did not provide enough time for large crystals to grow.