Is “ the banning of performance enhancing drugs in baseball has decreased the number of home runs hit each year “ a good thesis? if not explain why

It is not. Though the first part "the banning of performance enhancing drugs" is a good start, what follows seems to be an example rather than an argument to be explained. Remember that thesis statements are intended to express your opinion and give a general idea of the arguments that support it. These goals are not fulfilled, though it seems the author is against the banning, it is not explicitely said. And the arguments are not present. Also, the information is not logically presented.

imparadis't in one anothers arms  

the happier eden, shall enjoy their fill  

of bliss on bliss, while i to hell am thrust,  

where neither joy nor love, but fierce desire,  

among our other torments not the least,  

still unfulfill'd with pain of longing pines;  

yet let me not forget what i have gain'd  

from their own mouths; all is not theirs it seems:  

one fatal tree there stands of knowledge call'd,  

forbidden them to taste: knowledge forbidd'n?  

suspicious, reasonless. why should their lord  

envie them that? can it be sin to know,