Select the most correct statement.
a. the immune system is closely associated with the lymphatic system.
b. the endocrine system is not a true structural organ system.
c. organ systems operate independently of each other to maintain life.
d. organ systems can be composed of cells or tissues, but not both.

What is the difference between hypothesis, theories, laws, and observations?

Astudent wants to compare the amounts of co2 given off by yeast provided with different amounts of sugar. the student places a balloon over each container to catch the released co2. which observation is a qualitative observation the student can make?

Some animals shiver as a natural, involuntary response to their environment. shivering generates heat. this is an example of which function? reducing movement to regulate body temperature reducing movement to regulate blood glucose maintaining homeostasis by regulating body temperature maintaining homeostasis by regulating blood glucose