Question

when testing for tonicity of red blood cells, why were you unable to read the lab manual through the tubes containing hypertonic or isotonic solution? multiple choice because in both tubes the cells were so swollen that the solutions were opaque. because the concentrated salt solution was opaque before the blood cells were even added. because the cells in those solutions remained intact, causing the solutions to be opaque

Explanation:

In hypertonic and isotonic solutions, red - blood cells remain intact. Intact cells scatter light, making the solutions opaque and preventing reading through the tubes. In a hypertonic solution, cells shrink (not swell), and in an isotonic solution, they maintain their normal shape. The salt solution itself is not inherently opaque before adding cells.

Answer:

Because the cells in those solutions remained intact, causing the solutions to be opaque.