Because it helps enriches the soil, just like when you make home made compost you add egg shells and old veggies and stuff all the vitamins enriches the compost.
Hope this helped.
When the object has something added to it
There are 8 valence electrons in the Kr atom, this is because Krypton is in the 8th group. Krypton is in the far right row of the periodic table, making it the outermost shell (which is 8 valence electrons)
Hope this helps!
A hydrologist should analyze the water for contamination
