Help i have a headache;-;

Astructural difference between the trachea and esophagus that prevents the trachea from collapsing is the presence of: a) smooth muscle b) skeletal muscle c) respiratory cilia d) rings of cartilage

What ingredients used in tobacco products been banned?

While they impact the environment, recycling programs, emissions standards, and renewable energy development cannot reverse or stop the global warming problem. in which type of research paper would this thesis statement appear? a. analytical b. argumentative c. personal narrative d. how-to informational manual