Answer:
Science.
Step-by-step explanation:
There are 3 topics of science and I find all of them fairly complicated. Biology, the study of human, plants and animal, is one of the topic Ifinf facinating but it is also one of the hardest one I have ever learned. Chemistry, the study of atoms, particle and bonds, is ,no doubt, one of the hardest subject ever to be taught. I dont particulary enjoy it. Physics, the study of struture of matter, is a very interesting yet it is also like a endless supply of knowlegde.There is just so much to learn in Physic, whereter it be about space of about gravity.