Question

in this lab activity, students performed an experiment using eggs to observe the effect of osmosis on cells. the egg represented a typical cell. before beginning the experiment, students massed the raw eggs in vinegar to remove the shells. what they had in hand, then, was actually a raw, shell - less egg.
student procedure:
day 1 - students found the mass in grams of their shelled eggs, recording the mass in the data table. the eggs were placed in a beaker and covered with 200 ml vinegar to remove the shells. vinegar reacts with the calcium carbonate in the shell and the shell should disappear.
day 2 - the eggs were removed from the vinegar. visual observations were recorded. the shell - less eggs were wiped dry, massed, and the mass was recorded in the data table. the eggs were placed in and covered with a 10% salt - water solution.
day 3 - the eggs were removed from the salt water and visual observations were made and recorded. the eggs were wiped dry, massed, and the mass was recorded. the eggs were placed in and covered with sugar (karo) syrup.
day 4 - the eggs were removed from the syrup and visual observations were made and recorded. the eggs were carefully wiped with a damp cloth, massed, and the mass was recorded.
how do cells maintain water balance through osmosis? (choose 2)
a if a salt - water fish is placed in a fresh - water aquarium, water will leave the fish cells.
b in the experiment, the only hypertonic solution was the 10% salt - water solution.
c the egg swelled in distilled water because it is hypotonic to the eggs interior.
d the concentration of solute is greater inside the egg than it is in the karo syrup.
e the egg swelled when placed in a hypertonic solution.

Explanation:

Osmosis is the movement of water across a semi - permeable membrane from an area of lower solute concentration to an area of higher solute concentration. In option A, water moving from fresh water to salt water fish cells is an example of osmosis helping maintain water balance. In option E, an egg shrinking in a hypertonic solution shows water leaving the egg due to osmosis, which is also related to water balance. Option B is about a solution in an experiment and not about water balance through osmosis. Option C is about tonicity but not directly about how cells maintain water balance through osmosis. Option D is about solute concentration but not the mechanism of water balance through osmosis.

Answer:

A. If a salt - water fish is placed in a fresh - water aquarium, water will move into the fish cells.
E. The egg shrinks when placed in a hypertonic solution.