What caused the downfall of the han dynasty? ?

Has you probably know, Dynasties are just a long line of family members. Example: Mark Smith 1945, Sally Smith 1946, George Smith 1947. You get the idea.

But at the end of the Han dynasty, the last emperor was killed - and he wasn't married with kids.

the answer to your question is a because laws act as guidelines as to what is accepted in society. without it there would be conflicts between social groups and communities. it serves as a norm of conduct for citizens.