Question

investigation #1: what happens when you add a mentos to a bottle of diet soda ?
type :
benefit: no interference
limitation:

investigation #2: which bottle of soda shows the greatest reaction when mentos is added?
type : comparative
benefit: comparing two or more things
limitation:

investigation #3: how does the amount of mentos affect its reaction with a fixed amount of diet soda?
type : experimental
benefit:
limitation:

research required researcher bias variables not controlled descriptive hypothesis required
replication human error interferes with environment multiple trials retest for validity

Explanation:

Investigation #1

• Type: The question is about describing what happens, so the type is "descriptive".
• Limitation: Since it's just describing, there's no control over variables, so "variables not controlled".

• Limitation: In comparative studies, researcher bias can occur when the researcher interprets results based on preferences, so "researcher bias".

• Benefit: Experimental studies can have multiple trials to ensure reliability, so "multiple trials". Also, retesting for validity is a benefit. And replication is possible. Another benefit is that a hypothesis is required to guide the experiment.
• Limitation: Human error can occur during the experiment, and it might interfere with the environment (like the soda reaction might make a mess, interfering with the surroundings), also variables might still have issues, but common limitations here are "human error" and "interferes with environment".

Answer:

Type: descriptive
Limitation: variables not controlled

Investigation #2