Answer: last option, what came before the big bang?
Explanation:
The big bang theory states that the universe started as a dense nucleus of matter: a huge amount of matter concentrated in a tiny spot.
This is the conclusion of equations and evidences that prove that the universe has been and continuous to expand: since it has been expanding, there was a moment when it was as small and dense as it is possible.
So, the expansion is the result of violent explosion.
The time during which the expansion has been happening (this is how long ago the big bang occured) has been estimated thanks the the observation of the speed of recesion of the galaxies, but nothing can be told about what came before the bing bang occured.
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.
Talc is not a good choice when building a statue because the mineral Talc is one of the weakest minerals on the Mohs Scale with a hardness of 1 since it could be scratched by a fingernail, which means that when people build a statue with Talc, it could be easily broken down.
Answer:
A noncompetitive inhibitor can only bind to an enzyme with or without a substrate at several places at a particular point in time
Explanation:
this is because It changes the conformation of an enzyme as well as its active site, which makes the substrate unable to bind to the enzyme effectively so that the efficiency of the enzyme decreases. A noncompetitive inhibitor binds to the enzyme away from the active site, altering/distorting the shape of the enzyme so that even if the substrate can bind, the active site functions less effectively and most of the time also the inhibitor is reversible