Where does the oxygen/carbon dioxide exchange take place in the human respiratory system? please help me! A. bronchi
B. diaphragm
C. trachea
D. alveoli

Name the organs of humanelemintary canal.

Awave has a wavelength of 15 mm and a frequency of 6 hertz. what is its speed?

(select all the correct choose each statement that is scientific. - the opinions of randomly selected participants in a survey prove the idea that global temperatures are not increasing on earth. - the universe's average temperature and rate of expansion support the idea that it began as one super-dense and hot mass 13.8 billion years ago. - ocean tides are caused by the uneven gravitational pulls of the moon and sun on different parts of earth. - human life is more valuable than other forms of life on earth because humans are more intelligent than other organisms.