Questions: What method do researchers use to test their hypothesis and why? Choose all that apply. Comparison among species because some variables cannot be manipulated experimentally Experimental because researchers could vary just one factor at a time Experimental because researchers could vary many factors at a time Comparison between individuals within a species because no other species are comparable

Solution Steps

The question asks about methods for testing hypotheses related to adaptations in gulls for reducing predation. Specifically, we want to understand how researchers can test their hypotheses in this context, considering various experimental approaches and justifications.

Comparing among species is valid because some variables (like evolutionary history) cannot be manipulated experimentally. This approach helps identify correlations between traits (like nesting behavior) and predation rates across different gull species.

Experimental manipulation where researchers vary one factor at a time (e.g., nest location, camouflage) is a valid method. This helps isolate the effect of that specific factor on predation rates.

Experimental manipulation where researchers vary multiple factors (nest location, camouflage, parental behavior) is also valid. While more complex, this approach can reveal interactions between factors affecting predation.

Comparison within a species is less informative in this context because the hypothesis is about adaptations across species, not individual variation within a species. Such comparisons wouldn't address the broader evolutionary context.

Final Answer