Answer:
The mass of Uranium present in a 1.2mg sample is 
Explanation:
The ration between Uranium mass and total sample mass is:
For a sample of mass 1.2 mg, the amount of uranium is:

The Cell Membrane is what controls what enters and leaves the cell.
The sun is the primary source of light. Other artificial sources are light bulb, torch light and some others. Thats all i can think of.
Answer:
i d k about that but I know it`s a Polish thing
Mass is an independent quantity. It can neither be created nor be destroyed. So mass of giraffe will not change on moon.