My best guest is probably C or A.
The correct answer is C.
The egg sinks in freshwater because it is more dense than the water. So, to make the egg float, you would have to increase the density of the water. Since salt water has a greater density than freshwater, you would add salt to the freshwater, thus causing the egg to float rather than sink.
Answer: Sensitivity, reproduction, growth and development, regulation and energy processing
Explanation:
