Why are inheritance patterns more complex than simple patterns Mendel observed?

Mendels studies predicted inheritance in a simple manner by studying traits which were not continuous or polygenic. Hence, the patterns of Mendel's observations were simple.

But there are certain traits which are polygenic that means depending on more than one gene type and there are other traits which are continuous. These kinds of traits have complex inheritance patterns and cannot be predicted through laws of Mendel.

answer; i believe the correct answer is (sporophyte);

meiosis is the first to occur after the nuclei of opposite of opposite mating types fuse