In a particular region, most farms have livestock and crops. A survey of 21 farms showed that 15 grow crops, 9 have cattle, and 11 have sheep. Of these, 4 have sheep and cattle, 7 have cattle and crops, and 8 have sheep and crops. Two have neither animals nor crops.
(1) Display the information on a Venn diagram.
(2) Hence, find the number of farms with only crops.
(3) Hence, find the number of farms with only animals.
(4) Hence, find the number of farms with exactly one type of animal and crops.