Define ectoparasite and endoparasite and give suitable examples.

Despite interspecific competition in nature, which mechanism might competing species have evolved for their survival?

Select the correct option for the following organisms:
$I -$ Copepods,$II -$ Liver fluke,$III -$ Lice,$IV -$ Ticks,$V -$ Ascaris,$VI -$ Cuscuta
Ectoparasites $\quad\quad$ Endoparasites

Given below are two statements:
Statement $I$: Competition can be defined as a process in which the fitness of one species is significantly lower in the presence of another species.
Statement $II$: According to Darwin,interspecific competition is a potent force in organic evolution.

Study the following four statements $(1-4)$ and select the two which are correct:
$(1)$ Lion eating deer and sparrow feeding on grain are ecologically similar in being consumers.
$(2)$ The predator starfish $Pisaster$ helps in maintaining species diversity of some invertebrates.
$(3)$ Predators often lead to the extinction of prey species.
$(4)$ Production of chemicals such as nicotine and strychnine by plants is a metabolic disorder.
Which two statements are correct?

Small fish get stuck near the bottom of a shark and derive their nutrition from it. This kind of association is called as: