2. Which of the following could NOT be seen clearly by the unaided eye?

2. Which of the following could NOT be seen clearly by the unaided eye? Select all that apply.

A. Bacteria with diameter of 24 μm

B. Protozoa with diameter of 150 μm

C. Virus with a diameter of 0.2 μm

D. Skin cell with diameter of 1500 μm