When a pedigree is constructed, autosomal dominant disorders typically appear only in males appear only in females appear in every generation seem to disappear in one generation, only to reappear in the next generation?

I believe the answer is that they appear in every generation.
Autosomal dominant is a pattern of inheritance in which an affected individual has one copy of a mutant gene and one normal gene on a pair of autosomal chromosomes. Thus in an autosomal dominant disease, if you inherit the abnormal gene fro one parent, you can get the disease. 

That is true tge cactus as a structural adaptation to its envirinment has it leaves reduced to spines. but this doesnt mean it cant produce food it produces food because of the presence of chlorophyll in its stem