Question

investigation at the water hole.
the zoologists choose to conduct a comparative investigation, which involves more than just making observations of the behaviors of the animals at the watering hole. they want to know how many of each species of animals visit the watering hole in the winter months versus the summer months.
select the statement(s) which address the limitations of this type of investigation.
it will be difficult to find direct relationships.
the setting needs to be controlled.
the true behavior of the animal will not be on display.
there are many uncontrolled variables.
this investigation will interfere with the environment.

Explanation:

• In a comparative investigation, since it's an observational study in a natural setting (not a controlled experiment), there are numerous variables that can't be controlled (like weather, presence of other predators etc.), so "There are many uncontrolled variables" is a limitation. Also, because it's just observing and counting (not manipulating variables to see cause - effect), "It will be difficult to find direct relationships" is a limitation.
• "The setting needs to be controlled" is more of a requirement for a controlled experiment, not a limitation of a comparative investigation.
• In a natural - setting comparative investigation (at a water hole), the animals are in their natural environment, so their true behavior is likely to be on display.
• Just observing (counting species) at a water hole is a non - intrusive activity and is unlikely to interfere with the environment in a significant way.

Answer:

It will be difficult to find direct relationships; There are many uncontrolled variables.