The best answer to fill in the blank is "multilayered membrane."
Perhaps the answer is "physical characteristics". I am simply making an educated guess, however I do know early philosophers classified organisms into two groups, Plants and Animals, and identified them based on physical characteristics.
<span>the passing of fatal diseases from one organism to another hope this helps</span>
The answer is B. Heterotrophs. All animals and fungi are heterotrophs. Hope I helped!
