The small air sacs in the lungs through which gases are exchanged between the atmosphere and the blood are the __.
举一反三
- which type of epithelium is thin and leaky and lines blood vessels and the air sacs of the lungs A: Stratified squamous epithelium B: Cuboidal epithelium C: Simple squamous epithelium D: Simple columnar epithelium
- Ventilation in birds is accomplished by expansion and contraction of the ( ). A: air sacs B: trachea C: lungs D: diaphragm E: air capillaries
- If the _______ stops beating, no blood can flow through the body.() A: heart B: lungs
- 词汇与结构 This relationship between temperature, altitude, and air density can be expressed as a _______ altitude, or the altitude in the International Standard Atmosphere at which the air density would be equal to the actual air density.
- A process by which information is exchanged between individuals through a common system of symbols, signs, or behavior, or the exchange of thoughts, messages, or information, as by speech, signals, writing, or behavior.