<P> Invertebrates lack a liver , but most terrestrial groups , like insects , possesses a number of blind guts that serve the similar functions . Marine invertebrates do not need the ammonia conversion of the liver , as they can usually expel ammonia directly by diffusion through the skin . </P>
<P> Invertebrates lack a liver , but most terrestrial groups , like insects , possesses a number of blind guts that serve the similar functions . Marine invertebrates do not need the ammonia conversion of the liver , as they can usually expel ammonia directly by diffusion through the skin . </P>
where does diffusion occur in the excretory system
where does diffusion occur in the excretory system
diffusion
diffusion