During low exercise intensity levels you would still be able to sing. Correct answer: A Low-intensity exercise is exercise that gets you to about 40 to 50 percent of your MHR. Examples include a casual walk, a stretch session, a beginners' yoga class or tai chi... Low-intensity exercises can easily become moderate-intensity exercises by upping your pace. However while performing moderate activity you can talk, but you can't sing.
The answer here is B they are each made of matter. some are compounds, and some are elements they all contain Atoms this is because Silver and Oxygen are elements while Carbon Dioxide and Water are compounds. Although you do not have the choices down, I have come across this question before.
