Which of the following is an example of osmosis?
a. water leaves the tubules of the kidney due to hypertonic fluid surrounding the tubules.
b. digestive enzymes are excreted into the small intestine.
c. white blood cells consume pathogens at the site of an infection.
d. calcium is pumped inside a muscle cell after the muscle cell completes its contraction.

The correct answer is option A, that is, water leaves the tubules of the kidney due to hypertonic fluid surrounding the tubules.

Explanation:

Osmosis refers to a procedure by which the solvent molecules seem to go via a semipermeable membrane from a less concentrated solution into a more concentrated solution, thus equalizing the concentrations on both sides of the membrane.  

In the given question, an illustration of osmosis is when the water leaves the tubules of the kidney in response to the hypertonic fluid enveloping the tubules. In the kidneys, osmosis is a filtration. In the kidneys, osmosis will filter the molecules of water and solutes from the plasma to the tubules.  

•there must be variation for the particular trait within a population.

•the variation must be inheritable (that is, it must be capable of being passed on from the parents to their offspring).

•individuals with one version of the trait must produce more offspring than those with a different version of the trait.good

explanation: