Your answer would be D. You can find the neutrons by subtracting the mass by the atomic number. 14-6=8 neutrons.
Answer and Explanation: The excretory system helps the respiratory system by getting rid of carbon dioxide. The respiratory system helps the excretory system by getting rid of CO2 from the body. They both need each other and if one or the other did not exist, we might've not been able to survive. Tis demonstrates how vital they are for the human body.
The answer is A, 'a mammal' because it goes with the copulative verb 'to be', i. e., 'is'.
