Answer:
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Answer:
A. A scientist investigates a mouse's growth in nature by watching the animal.
A field study is a raw collection of data, typically in the natural habit of the organism; hence why an experiment taken in a lab isn't a field study.
Answer : Yes, a precipitate form when a solution of calcium chloride and a solution of mercury(I) nitrate are mixed together.
The net ionic equation will be,

Explanation :
In the net ionic equations, we are not include the spectator ions in the equations.
Spectator ions : The ions present on reactant and product side which do not participate in a reactions. The same ions present on both the sides.
The given balanced ionic equation will be,

The ionic equation in separated aqueous solution will be,

In this equation,
are the spectator ions.
By removing the spectator ions from the balanced ionic equation, we get the net ionic equation.
The net ionic equation will be,

156. Atomic mass if the number of protons and neutrons within an atom.