Answer:
D. tip his head back farther to open his airway.
Explanation:
Tilting the head farther back moves the tongue away from the back of the throat, allowing air to enter the lungs.
The answer is 'The Biosphere.'
Well, first off the spongy mesophyll does have some chloroplasts, however they are located quite far from the surface of the leaf where most of the chloroplasts are. Therefore they don't get much light and don't contribute a lot to photosynthesis in the leaf. So why should the leaf waste the energy in making chloroplasts if there is not enough light to make them all efficient enough at photosynthesis?
The answer would be osmosis
A dependent variable is something that relies on another variable; it is what is being measured in an experiment.