The plurals are boxes, sheep, and princes.
deer fish sheep
Yes, words that keep the same form in singular and plural are considered irregular plurals. Examples include sheep, deer, and aircraft.
3 (oxen, horses and geese)
The number of sheep that can fit in a phone box would depend on the size of the box and the size of the sheep. As a rough estimate, assuming an average phone box size and average sheep size, you could fit around 10-15 sheep in a phone box.
NO.
Some irregular plural nouns have the same spelling as their singular form such as scissors, pants, bison, deer, and sheep.
I don't think there is a rule, just that some nouns have identical forms: sheep, species, deer, aircraft are some examples.
The little prince asked the narrator to draw hima sheep
The forming of plurals by adding 's' was introduced by the Norman French who invaded England after 1066. Prior to that the German technique of adding -en was used. In farming communities (especially remote sheep farms) the old ways of spelling and pronunciation hung on. (Sheep farmers in Yorkshire still count using Gaelic from ancient British times). The more common the word the less likely it was to change from germanic to french as people were too used to it to want to change. So words like man, woman, child, goose, deer, sheep, fish have irregular plurals.
The singular and plural are the same word, for example: one sheep, two sheep, three sheep. Examples: Mary had a little lamb that grew up to be a sheep. When Mary grew up, she kept a flock of thirty sheep.
pluralsThe word plurals is the plural of plural. As in: I answered the question about plurals to the person who didn't know that the plural of plural is plurals.
The two plurals of "vortex" are "vortexes" and "vortices".