Answer:
the limitation of his investigation is amount of involvement that he can have.
Step-by-step explanation:
By choosing a descriptive investigation method, the student is limited to creating a highly detailed description of the bacteria but cannot investigate and answer the more important questions such as how to grow the bacteria. An experimental investigation would allow the student to test different methods of growing the bacteria and compare them to see which one is actually the most effective. Thus the limitation of his investigation is amount of involvement that he can have.