Which of the following statements is false? Unselected We clear and swallow over 2 million alveolar macrophages per hour. Unselected Alveolar surfaces are usually sterile. Unselected Remarkably efficient alveolar macrophages crawl freely along the internal and external alveolar surfaces. Unselected Huge numbers of infectious microorganisms are continuously carried into the alveoli.

Remarkably efficient alveolar macrophages crawl freely along the internal and external alveolar surfaces

Explanation:

The alveolar macrophages are present on the internal lumenal surfaces of the alveolar ducts,  the alveoli, and the bronchioles.

Alveolar macrophages are phagocytes that uses several surface receptors to release many secretions, to interact with other cells and molecules.

But the alveolar macrophages are intact to the inner surface only and do not crawl freely along the internal and external alveolar surfaces.

Hence, the correct option is " C".

the element that provides strength to the exoskeletons of clams and oysters is phosphorus.

this is so because calcium carbonate is the main component in the shells. calcium carbonate is strengthened by phosphorus.

explanation:

d. organisms have cells with different shapes and functions.