"Preserving and staining samples for use with light microscopes is necessary; preserving and staining samples for use with electron microscopes is optional"
that is the correct answer
Answer:
A
Explanation:
The correct answer is A. constant since it's not gaining or losing matter.
Answer:
Two types are pneumocytes known as type I and type II cells found in the alveolar wall, and a large phagocytic cell known as an alveolar macrophage that moves about in the lumens of the alveoli, and in the connective tissue between them. Type I cells are squamous, thin and flat and form the structure of the alveoli.
Explanation: Look it up and you will find your answer :)