Sorry this will probably be pretty long.
So think of the "control" as being something you yourself add to increase or decrease the effects in an experiment.
I'll give you an example so it is not as confusing.
Say you have decided to make an experiment on plants. Which plant can grow the fastest on which type of liquid? What is being added to this experiment? The liquid! Or all of the liquids you used. Like if you used Coke, Lime Gatorade, Orange Gatorade, and Water. Each drink will EFFECT each plant differently.
Hope I was of any hope?
Answer:
an object that is at rest will stay at rest inless a force acts upon it.
An oject that is in motion will not change its velocity unless a force acts upon it.
Answer:
\frac{dh}{dt}_{h=2cm} =\frac{40}{9\pi}\frac{cm}{2}
Explanation:
Hello,
The suitable differential equation for this case is:
As we're looking for the change in height with respect to the time, we need a relationship to achieve such as:
Of course, 
.
Now, since the volume of a cone is 
and the ratio 
or 
, the volume becomes:
We proceed to its differentiation:
Then, we compute 
Finally, at h=2:
Best regards.
The correct option is COVALENT BONDS.
A Lewis acid is defined as a substance which accept a pair of electron while a Lewis base refers to a substance that donate an unshared pair of electrons to another chemical specie with which it shared the donated pair of electrons.
Lewis acid and Lewis base react together to form salt and water. This type of reaction is called neutralization reaction. The neutralization reaction of Lewis acid and Lewis base involves electron pairs transfer, thus, there is an increase in the number of covalent bonds during this reaction.
