Answer:
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".
B. The levels of classification increased. Previously there were only 2 domains of life, Bacteria and Eukarya, but an additional domain and Kingdom were added when the distinction of Archaea was observed.
The answer is copper. Nonrenewable resources are those that cannot be readily/naturally replaced at rates that match those of consumption (an aspect that allow renewable resources to be sustainable). Copper are made deep in earth at very slow rates hence do not readily renew themselves. Organisms, on the other hand die, and are naturally replaced by offspring.
