Answer:
The concentration of this solution in units of pounds per gallon is 
Explanation:
Units of measurement are established models for measuring different quantities. The conversion of units is the transformation of a quantity, expressed in a certain unit of measure, into an equivalent one, which may or may not be of the same system of units.
In this case, the conversion of units is carried out knowing that 1 μg are equal to 2.205*10⁻⁹ Lb and 1 mL equals 0.00022 Gallons. So

If 1 μg equals 2.205*10⁻⁹ lb, 2.77 μg how many lb equals?

lb=6.10785*10⁻⁹
So, 2.77 μg= 6.10785*10⁻⁹ lb
Then:

You get:

<u><em>The concentration of this solution in units of pounds per gallon is </em></u>
<u><em></em></u>
I dont understand , what u write
Answer: C. variable depending on where its found
The chemical compositions of minerals is very necessary in order to define or describe a certain mineral. Some minerals can be written in simple chemical formula while others are also written in complicated chemical formulas.
Answer:
Earth is the only planet in our solar system that has a large amount of liquid water. About 74% of the surface of Earth is covered by liquid or frozen water. Because of this, people sometimes call it the blue planet. Because of its water, Earth is home to millions of species of plants and animals.
Explanation:
Earth is the only planet in our solar system that has a massive quantity of liquid water. About 74% of the surface of Earth is covered with the aid of liquid or frozen water. Because of this, people on occasion name it the blue planet. Because of its water, Earth is domestic to thousands and thousands of species of flora and animals.