My science text book said that it was either diamond or gold. Gold may not be right, but I am pretty sure diamond is.
Sorry if I got this wrong.
Almost always, the first way in which biology researchers present the results of their latest research is to discuss the results of previous research that they want to build off of.
Answer:

Explanation:
Given:
A solution contains one or more of the following ions such as Ag,
and 
Here the Lithium bromide is added to the solution and no precipitate forms
Solution:
Since with LiBr no precipitation takes place therefore Ag+ is absent
Here on adding
to it precipitation takes place.
Precipitate is as follows,

Thus,
is present
When
is added again precipitation takes place.
Therefore the reaction is as follows,

Therefore,
are present in the solution
A glass jar sitting on a shelf.
If the shelf gets tipped the jar will slide off and convert to kinetic energy as gravity pulls it to land on the next level/floor