B. each system works independently to stabilize the body
Because the moon orbits the earth and when the moon gets in front of the sun it blocks the sunlight and then it becomes night
Answer : The Lewis-dot structure of
is shown below.
Explanation :
Lewis-dot structure : It shows the bonding between the atoms of a molecule and it also shows the unpaired electrons present in the molecule.
In the Lewis-dot structure the valance electrons are shown by 'dot'.
The given molecule is, 
As we know that rubidium has '1' valence electrons, iodine has '7' valence electrons and oxygen has '6' valence electrons.
Therefore, the total number of valence electrons in
= 1 + 7 + 2(6) = 20
As we know that
is an ionic compound because it is formed by the transfer of electron takes place from metal to non-metal element.
Carbon will have 4 valence electrons. It will have 2 in the p orbital and 2 in the s orbital. You can see this when you find the noble gas configuration of carbon which is [He]2s²2p² showing that carbon has 4 valence electrons.
I hope this helps. Let me know if anything is unclear.