According to the information given in the exercise, the daily supply of oxygen for a particular multicellular organism is provided by 625 square feet of lawn:

Let be "x" the number of multicellular organisms that will receive the daily supplies provided by a total of 10,625 square feet of lawn.
Using the data provided in the exercise, you can set up the following proportion:

Therefore, solving for the variable "x", you get this result:

Hence, the answer is: 17 organisms.