$\bullet$ Amensalism is an interaction between two organisms of different species in which one species inhibits the growth of other species by secreting certain chemicals. The first species is neither get benefited nor harmed.

$\bullet$ (+) : (0) interaction is observed in commensalism.

$\bullet$ (+) : (+) interaction is observed in mutualism.

$\bullet$ ($-$) : ($-$) interaction is seen in competition.