This is actually a science question, this is because the air particles with the warmer temperature always go up and air particles with the cooler temperature always goes down, and this process is called convection.
I hope this could help you ;)
Answer:
Perimeter: 88m
Step-by-step explanation:
Area of the square plot = (Side) X (Side)
And we are given the area is 484m²,
therefore, (Side) X (Side) = 484m²
or,
(Side)² = 484, taking square root on both the sides,
= 
Side = 22m.
And we know that, perimeter of a square is = 4 X (Side)
Therefore, Perimeter = 4 X 22 = 88m
:-)
Answer:
B If a quadrilateral has diagonals that bisect each other, then the quadrilateral is a parallelogram
Explanation:
A rectangle just like a square has diagonals that bisect each other and they are congruent( two lines are congruent if they are equal). A parallelogram is a quadrilateral with parallel sides and when its diagonals intersect, they are congruent too. Therefore a rectangle with diagonals that bisect each other is not necessarily a parallelogram.
Answer:

Step-by-step explanation:
In 5 liters, there is 4% salt.
Lets find liters of salt.
First, converting 4% to decimal (dividing by 100):
4% = 4/100 = 0.04
0.04 * 5 = 0.2
So, there is 0.2 liters of salt.
Now, x liters of water is added to total, so total is now:
5 + x
The concentration of salt will be amount of salt divided by amount of salt water solution.
Amount of salt = 0.2 (as seen above)
Amount of new salt water solution = x + 5
So,
Concentration of salt in new solution is 
2nd choice is right.
Answer:
C; A singleton set
Step-by-step explanation:
Mathematically, when a number is non-negative; it is either positive or zero
Now, this is because 0 identifies as neither a positive or a negative number
hence, when we find the difference between the two sets, the only number that stands out unmatched is the value 0
What this mean is that we are having a set with a single number result
So we have our answer as {0}
Which is a singleton set