D) laboratory experiments because every experiment needs a control and a variable.
<span>B. A secondary consumer that obtains its energy from the consumption of animals.
The red-tailed hawk is a secondary consumer because it feeds itself on primary consumers (those that eat plants, herbivores). Secondary consumers, by definition, </span><span>obtain their energy from eating other animals. Secondary consumers are also usually the ones that stand on the second and above rows of a food chain, being the plants at the bottom and the primary consumers just above the plants.</span>
