Which body systems help to exchange oxygen and carbon dioxide? A. respiratory and digestive
B. circulatory and digestive
C. respiratory and circulatory
D. digestive and excretory

2points why do scientists need governmental funding? o a. government politicians ask all the important scientific questions. o b. scientists have to pay taxes to the government on the money they make. o c. the cost of doing scientific research can be very high. o d. the government is controlled by scientists. submit

What are transitions between a liquid and a solid called? identify which way they are transitioning

Chen drew a diagram to compare the ways in which different organisms obtain nitrogen. which label belongs to the area marked z?