Which system improves the way your heart works?
a. circulatory
b. mental
c. nervous
d. respiratory

Look at the following answer choices and determine which belongs in the both category. testable, can be disproven explains natural phenomena, has evidence to support it prediction, tentative, one or more scientists working together well established, many different scientists working independently, highly reliable

Which of the following is a common danger of commercial fishing?

What would happen if the tubing with the yellow band was placed in a beaker of distilled water?