Question 1:
respiration
A. mouth
B. circulation
C. oxygen
Feedback A person or animal must take in oxygen for respiration to occur. A mouth (choice a) is not essential because breathing can occur through the nose. Choices b and d are clearly not essential and can be ruled out.
D. carbon monoxide

These questions are from this test. Would you like to take a practice test?

Practice Essential Parts Online Test 1 | Englishfreetest.com