The answer to your question is dioxygen carbide
This type of listening response is called back-channel signal. This allows the speaker to know that the listener is attentive or willing to engage a conversation between them. It is shown through short utterances, facial expressions, head nods and others.
3, protons are positive and there are 3 positive atoms visible
If you write down the formula for friction, you will get an answer.
Ff = u * N Where N is a push down force that an object experiences.
u (mu) is a constant and has no units
It may not be accelerating and still experience friction. A is not correct.
Color and Density will not affect the frictional force. B is not so.
Buoyant forces are a different thing altogether. Generally friction has nothing to do with them. C is incorrect.
The last one is your answer. Technically mg should be the answer and not mass, but the second part is correct.