To find the net ionic equation we must first write the balanced equation for the reaction. We must bear in mind that the reagents Ca(NO3)2 and Na2S are in the aqueous state and as product we will have CaS in the solid state, since it is not soluble in water and NaNO3 in the aqueous state.
The balanced equation of the reaction will be:

Ca(NO3)2(aq) + → Ca(aq) + 2Na(s)NO3Now, c(aq)ompounds in the aqueous state can be written in their ionic form, so the reaction will transform into:Na2S +

So, the answer will be option A
Ultraviolet helps bee's see depth and they can see 3 dimensional, they can also see long distance. Bee's have have single lenses that helps the bee maintain stability and navigate.
Short Answer: Ultraviolet vision helps bees help detect UV flower colors
- Hope this helps!
The plants without any fertiliser could be the control, to see what the change in the independent variable (fertiliser) does to the growth of the plant (dependant variable).
Hope that helps.