Question

a group of students plan to use five elodea leaves to conduct a similar investigation that includes using a microscope to make observations. which procedure would best allow the students to determine the effects of multiple concentrations of salt solutions on the cells in the leaves?

a prepare four solutions with different concentrations of salt, apply each salt solution to a different leaf, place the last leaf in distilled water, and then make drawings of the observations of cells from each leaf.

b apply a random saltwater solution to all the leaves, observe any changes in cell structure, and then repeat with a different random saltwater solution until the solution has been applied to all leaves.

c randomly apply five solutions with different salt concentrations to different leaves, and use a ruler within a microscope to determine which solution was applied to each leaf based on the cell size.

d prepare one salt solution, apply the solution to four leaves, keep the last leaf in aquarium water, and then estimate the effects of the solution by measuring changes in each leaf’s cell size.

Explanation:

To determine the effect of multiple salt concentrations on Elodea leaf cells, a controlled experiment with different concentrations (including a control like distilled water) is needed. Option A uses 4 different salt solutions (one per leaf) and a control (distilled water on the fifth leaf), then observes cells. Option B uses random solutions, lacking control. Option C randomly applies solutions and tries to identify them post - observation, which is not a valid experimental design. Option D uses only one salt solution, so it can't test multiple concentrations. So Option A is the best procedure.

Answer:

A. Prepare four solutions with different concentrations of salt, apply each salt solution to a different leaf, place the last leaf in distilled water, and then make drawings of the observations of cells from each leaf.