When it contracts, the difference in air pressure forces air into the body * cell
tissue
organ
organ system

Which of the following is the earliest era of earth's geologic time scale? cenozoic mesozoic precambrian paleozoic

Astudent poured a solution of bromothymol blue indicator into three test tubes. then he placed an aquatic plant in two of the test tubes, as shown below. he placed a stopper on each test tube and placed them all in the dark for 24 hours. bromothymol blue turns from blue to yellow in the presence of co2

Which organ controls breathing? lungs alveoli heart diaphragm