Koalas do not take showers.
Shower, most likely. If the water temperature is the same, then it all depends on the amount of water used. If you take short showers, then showers use less energy. If you take super long showers, then either take a bath, or hurry up. I'd think that it's more common to take cold showers than cold baths as well.
3-4 showers a week might be enough if they are not active, but a bath everyday is better.
1 or 2 should be fine
People take showers to wash away dirt, sweat, oil, and body odor.
None, a dog should only get bathed when it's really, really dirty.
There is nothing bad about baths! I think that only little kids should take baths though! And adults and teenagers should take showers!
It is possible to take cold showers during the winter, though it may be uncomfortable.
no
yes
yes
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