Which circuit style of holiday (christmas) lights would be best to have and why?
mini lights

The best circuit style of Holiday (Christmas) Lights would be Parallel circuit.

Explanation:

Because if one lights goes out all of the other lights stays on.

SERIES-PARALLEL

Explanation:

In a series connection, all light bulbs or LEDs are connected to one source and if one of the connecting bulbs burns out, then the remaining bulbs will not light.

In a parallel connection, all bulbs are lighted directly from the power source and as such, if a light bulb is disconnected, other bulbs will still light.

Therefore, it is best for a Christmas light to have a series-parallel connection in the manner of the second picture i.e each segment is first connected in parallel and then in series, this way, if a segment is disconnected, other segments would still light as they do not take power from the disconnected segment.

c)as speed changes, wavelength and frequency change.

everything changes!

come closer and become far apart and become steam/gas