Question

how is a cell membrane identified when using a brightfield microscope?
a. darker outline of a cells shape.
b. darker circle inside of a cell.
c. purple strands inside of a cell.
d. clear area near the apical surface of a cell.
which of the following best defines a tissue?
a. group of fibers that work to connect two cells.
b. group of organelles that work together to perform a common function.
c. group of organs that work together to perform a common function.
d. group of similar cells and surrounding material that perform a common function.

Explanation:

For the first question, under a bright - field microscope, the cell membrane appears as a darker outline of a cell's shape due to differences in refractive index. For the second question, by definition, a tissue is a group of similar cells and surrounding material that perform a common function.

Answer:

A. A darker outline of a cell's shape
D. Group of similar cells and surrounding material that perform a common function