$\forall x(H(x)\rightarrow\forall y(E(y,x)\rightarrow A(y)))$
$1) \forall x(H(x)\rightarrow$
For all $x$, if $x$ is a human, then (for anybody who is a human)
$2)\forall y(E(y,x)\rightarrow$
for all $y$, if $y$ eats $x$, then (for anybody who eats human)
$3)A(y))$
$y$ is an alligator. (that anybody is a alligator)
For all x if $x$ is a human and if $x$ is eaten by some $y$ and that $y$ is an alligator.
So, Only $alligator$ eats human.