$A$ relationship in which a sea anemone is attached to the shell of a hermit crab is called:

Which of the following is most commonly cited as a predator?

Given below are two statements:
Statement $I$: Gause's competitive exclusion principle states that two closely related species competing for different resources cannot exist indefinitely.
Statement $II$: According to Gause's principle,during competition,the inferior will be eliminated. This may be true if resources are limiting.
In the light of the above statements,choose the correct answer from the options given below :

Which of the following is correctly categorized as a parasite?

Which one of the following shows interspecific competition?

Choose the correct statements regarding population interactions between two species.
$A$. In both parasitism and commensalism, only one species benefits and the other species is harmed.
$B$. Both species benefit in mutualism.
$C$. Both species benefit in commensalism.
$D$. In parasitism, only one species benefits and the other species is harmed.
$E$. In amensalism, one species is harmed and the other is unaffected.