Air moves out of the lungs when the
(a) diaphragm relaxes and the rib cage moves inward.
(b) air pressure inside the lungs is less than the external air pressure.
(c) diaphragm contracts and the rib cage expands.
(d) air pressure inside the lungs is the same as the external air pressure.

Which of the following is an oxidation-reduction reaction? (pictured below)

(drag each tile to the correct location.) categorize each term as something that is typical of a scientific theory, a scientific hypothesis, or both. - a tentative statement used to guide scientific investigations. - makes predictions about future events. - can be tested by many independent researchers. - based on observations of natural phenomena. - a well-established, highly reliable explanation.

Compare and contrast cladistics and phylogeny. what are their advantages and disadvantages? which is the most useful in understanding how an organism developed into its current form? which concept most strongly supports your opinion about the origin of any given organism?