Question

developing ideas quick check
\why are yawns contagious? we asked a scientist\
by tonia camp
why do we yawn?
there is no generally consensus on why we yawn. one theory argues that when humans are tired, we stop taking deep breaths, which causes a buildup of carbon dioxide in the body, said andrew gallup, a queen scientist at witsons hills university. a yawn might be a means of respiration. yawning, said gallup, builds up oxygen quickly, while expelling carbon dioxide, even more than a deep breath.
yawning causes other chemical changes, such as a drop in oxygen or increase in a compound called adenosine, could also all we start yawning, said james giordano, a neuroscientist at georgetown university. these chemicals send out a signal that triggers a yawn. by yawning we contract the muscles of the face, driving oxygen-enriched blood to the brain, giordano said.
other important roles the purpose of yawning is to cool the brain, or to stretch internal organs like muscles and lungs, relaxing the body to...
use the passage from why are yawns contagious? we asked a scientist to answer the question
effect: we yawn.
cause: to quickly expel carbon dioxide
cause: to drive oxygen - enriched blood to the brain
cause: to stretch internal organs
cause:?
cause:?
based on the information in the passage, which causes complete the graphic organizer? select the two correct answers. (1 point)
☐ to cool the brain
☐ to build up oxygen
☐ to increase the frequency of deep breaths
☐ to facilitate cellular waste
☐ to strengthen facial muscles

Explanation:

1. The passage states that a drop in oxygen or increase in adenosine can trigger yawns, so reducing adenosine levels is a related cause.
2. The passage also notes that yawning stretches internal organs like muscles and lungs, which helps the body relax.

Answer:

• to reduce adenosine levels
• to relax the brain