During inhalation, view available hint(s) during inhalation, oxygen molecules move into the lungs, and carbon dioxide molecules move out of the lungs. the volume of the thoracic cavity decreases. air moves up the trachea. the diaphragm relaxes. the diaphragm and rib muscles contract.

the diaphragm and rib muscles contract

Explanation:

Inhalation is the set of movements that allows air to enter the lungs. In this process occurs the contraction of the diaphragm, causing its lowering. The intercostal muscles also contract causing the ribs to lift. This causes the chest to grow larger and the internal pressure of the lungs to become smaller than the external. With the reduction of intrapulmonary pressure, air ends up entering the airways and reaching the alveoli for gas exchange to occur.

in the given question, the partial pressure is calculated by using the ideal gas equation, that is, pv = nrt

here, p is pressure, v is volume = 25 l, n is number of moles = 0.0104 moles, r is gas constant = -0.0821 l.atm / mol.k

t is temperature = 273 k

p = nrt / v

p = (0.0104 mol × 0.0821 l.atm / mol.k × 273 k) / 25 l

= 0.0093 atm

1. the question asks the most appropriate, which seems to rule out "all of the above." your choice appears to be the correct one.

2. the protocol described is good for identifying correlation, but not cause and effect. for cause/effect, you need to devise a protocol that will assign the treatment (or not) to groups that have essentially the same "demographics" with respect to all the other variables. your choice regarding control group seems appropriate. random assignment of treatment (choice d) may be appropriate also. (i think you can argue that b and d are just different descriptions of the same method.)

3. d will randomize the birds, but may not guarantee there are 10 in each group. e will do both, so seems the better choice.

comment on question 2

based on the problem statement, it seems clear that confident, attentive drivers are more likely to use daytime running lights. so, the protocol might need to be devised in such a way that the lights would be turned on or off without the driver's knowledge. (an attentive driver will figure it out.) assigning a confident, attentive driver to a group required to drive without running lights might mess with his/her confidence and attentiveness. you don't want your experiment to do that. (nor do you want the experiment to subject a driver to greater risk of accident as a consequence of driving without running lights.) experiments involving human safety are always problematic.