Which evidence from the sea floor shows that tectonic plates move ? a) The sea floor is much older than any of the continents. b) The sea floor is youngest near a mid-ocean ridge and older farther away. c) Mid-Ocean ridges circle Eqarth like seams in a baseball d) The sea floor is thinner than continental crust.
The trachea, colloquially called the windpipe, is a tube that connects the pharynx and larynx to the lungs, allowing the passage of air, and so is present in almost all air-breathing animals with lungs.he trachea is lined with a layer of pseudostratified columnar epithelium, a type of epithelium. The epithelium contains goblet cells, which are glandular, modified simple columnar epithelial cells that produce mucins, the main component of mucus. Mucus helps to moisten and protect the airways.
Trachea. The trachea is a wide flexible tube, the lumen of which is kept open by 20 tracheal cartilages, which are C-shaped rings of hyaline cartilage. The gaps between the rings of cartilage are filled by the trachealis muscle-a bundle of smooth muscle, and fibroelastic tissue.he epithelium is either columnar or cuboidal. The final branches of the bronchioles are called terminal bronchioles. These have a layer smooth muscle surrounding their lumens. Stimulation of the vagus nerve (parasympathetic) causes the smooth muscle to contract, and reduce the diameter of the terminal bronchioles.