It is a stimulus because parts of the ear respond to exact stimuli which would make this a stimulus. Our bodies make us able to hear normally but some people's bodies are not able to respond to the stimuli which unfortunately explains deaf people.
Hope this helps! Would love brainliest if possible:)
Yikes it depends. did you eat something that could have been unsafe to consume?
Pulmonary circulation transports oxygen poor blood from the right ventricle to the lungs to get oxygenated.