Final answer:
The best characteristic of living things to look for under a microscope is cells, which are the basic units of life. Special stains are used to make the components of cells more distinguishable under a light microscope.
Step-by-step explanation:
The BEST characteristic of living things for Dani and Alex to look for using a microscope would be Cell(s). Cells are the basic units of life and are essential to all living organisms. When viewing specimens under a light microscope, scientists often use special stains, as mentioned in the provided reference content, to make the individual components of the cells more visible since they lack color and are transparent.
Regarding the review questions, the method scientists use to make it easier to see individual components of cells is special stains (Answer to Review Question 1: d. special stains). As for the basic unit of life, the answer is cell (Answer to Review Question 2: a. cell).