Answer: Option (C) is the correct answer.
Explanation:
When chemical composition of a substance is not changing in a chemical reaction then it is known as a physical change.
For example, when water change state, from ice to steam then it means solid state is changing into gaseous state.
Therefore, it is a physical change.
And, a reaction which causes change in chemical composition is known as a chemical change.
For example, 
Thus, we can conclude that we can see water change state, from ice to steam. This is a physical change in matter.
Answer:
Water gradually degrades them until the metal parts rust and the other materials deteriorate.
Explanation:
Answer:D molecular attraction increases as temp decreases
Explanation:A,B would require data not available. C is missing. The question is a mess.
Answer : The number of moles of oxygen needed are, 1.5 moles.
Explanation :
The balanced chemical reaction will be:
Now we have to calculate the moles of oxygen.
From the balanced chemical reaction we conclude that,
As, 6 moles of water vapor produces from 5 moles of oxygen
So, 1.80 moles of water vapor produces from 
moles of oxygen
Therefore, the number of moles of oxygen needed are, 1.5 moles.
The valves stop the blood from flowing backwards
