Answer:
c
Explanation:
you don't think of particles as dense and less dense
dust particles containvenergy but won't release it unless acted upon a force
gas molecules move freely and collide with dust particles which is correct
P and S
___________________________________________________________
12 times breathe give 240 ml of pure 
. Each breathe gives 20 ml of .
Let us consider, volume of air per breathe= x ml.
Pure from inhaled air= 
ml and Pure from exhaled air= 
ml.
Pure from inhaled and exhaled air= 20 ml
So, + = 20
Therefore, x = 55.5 ml
So, volume of air per breath= 55.5 ml.
elements:
calcium : for strong bones
Iron : maintaining haemoglobin for metabolism
compunds
sodium chloride : to maintain blood pressure and other life processes
Adenosine Triphosphate: for metabolism, to maintain rate of inhalation and exhalation of oxygen and to supply energy
Mixture:
I) gasoline : used as fuel
ii) cement : used in construction
Explanation:
A metal with one valence electron is highly reactive compared to those with more than one electron.
Atoms including those of metals reacts in order attain a stable electronic configuration just like those of noble gases.
An atom with one valence electron have just one electron in its valence shell.
- Metals generally have large sizes.
- when the electron in this shell is lost, the metal atom can then attain stability.
- therefore, such atom will quickly want to combine with any other willing to accept the electron so that they can be stable.
- Those with more than one electron will find it difficult to lose them.
- It requires huge energy to remove such electrons compared to the ones with only one valence electron.
learn more:
Valence electrons brainly.com/question/3023499
#learnwithBrainly
