To check for consciousness: a) lift an eyelid to see if their pupils are dilated b) check their pulse c) tap the person and ask if they are okay d) listen for a heartbe

Tap the person and ask if they are okay (Option C )

Explanation:  

In order to check for consciousness, it basically involves examining a person to conclude if the person is conscious or unconscious. If the person is conscious then you could ask her/him that are you okay?

However, if the person is unconscious you need to check the pulse to check if the heart is beating or not.

relationship between pressure and air volume and led to the understanding of how respiration works; i believe this is the correct answer ; /// good luck