3. Endotherms spend more energy on internal temperature regulation compared to ectotherms.
Explanation:
Ectotherms, are considered as cold-blooded animals (reptiles and amphibians), and are organisms that don't have the ability to generate enough heat to keep themselves warm. Endotherms, in contrast, do possess the ability to generate their own body heat.
Endotherms also called warm blooded animals (mammals) have the ability to regulate their body temperature by themselves. If the endotherms are in a cold place their body increases the metabolism and generates more heat. This will compensate for the cold outside.
Student 1’s methods would be more accurate, because the student would control more factors. Only one variable at a time (either temperature or acidity) would be tested on each group of worms. On the other hand, Student 2 is testing both factors on all the worms, which could make the results unclear.